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Home Lớp 7 Toán lớp 7 - Sách kết nối tri thức Nhân, chia số hữu tỉBài tập cơ bản

{"common":{"save":0,"post_id":"958","level":1,"total":20,"point":5,"point_extra":0},"segment":[{"id":"101","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":" Vi\u1ebft s\u1ed1 h\u1eefu t\u1ec9 $\\dfrac{-9}{28}$ d\u01b0\u1edbi d\u1ea1ng t\u00edch c\u1ee7a hai s\u1ed1 h\u1eefu t\u1ec9. K\u1ebft qu\u1ea3 n\u00e0o sau \u0111\u00e2y l\u00e0 sai?","select":["A. $ \\dfrac{-9}{28} = \\dfrac{-9}{7} . \\dfrac{1}{4}$","B. $ \\dfrac{-9}{28} = \\dfrac{9}{4} . \\dfrac{-1}{7}$","C. $ \\dfrac{-9}{28} = \\dfrac{-9}{28} . 1$","D. $ \\dfrac{-9}{28} = \\dfrac{-9}{4} . 4$"],"hint":" \u00c1p d\u1ee5ng quy t\u1eafc nh\u00e2n hai s\u1ed1 h\u1eefu t\u1ec9","explain":"Ta c\u00f3: $ \\dfrac{-9}{28} = \\dfrac{-9}{7} . \\dfrac{1}{4} = \\dfrac{9}{4} . \\dfrac{-1}{7} =\\dfrac{-9}{28} . 1 $ <br\/> C\u00e2u sai l\u00e0 D v\u00ec: $ \\dfrac{-9}{28} \\neq \\dfrac{-9}{4} . 4 = -9 $ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"102","post_id":"958","mon_id":"0","chapter_id":"0","question":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","options":{"time":9,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["7"],["9"]]],"list":[{"point":5,"width":50,"ques":" S\u1ed1 ngh\u1ecbch \u0111\u1ea3o c\u1ee7a $1\\dfrac{2}{7}$ l\u00e0: <div class=\"frac123\"><div class=\"ts\">_input_<\/div><div class=\"ms\">_input_<\/div><\/div>","hint":" S\u1ed1 ngh\u1ecbch \u0111\u1ea3o c\u1ee7a $\\dfrac{a}{b}$ l\u00e0 $\\dfrac{b}{a}$","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * S\u1ed1 ngh\u1ecbch \u0111\u1ea3o <\/b> <br\/> S\u1ed1 ngh\u1ecbch \u0111\u1ea3o c\u1ee7a $\\left( \\dfrac{a}{b} \\right)$ l\u00e0 $\\left( \\dfrac{a}{b} \\right)^ {-1}$ v\u00e0 $\\left( \\dfrac{a}{b} \\right)^ {-1} = \\dfrac{b}{a}.$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> Ta c\u00f3: $1\\dfrac{2}{7} = \\dfrac{9}{7}$ <br\/> Suy ra s\u1ed1 ngh\u1ecbch \u0111\u1ea3o c\u1ee7a $\\dfrac{9}{7}$ l\u00e0 $\\dfrac{7}{9}$"}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"103","post_id":"958","mon_id":"0","chapter_id":"0","question":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","options":{"time":9,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["7"],["2"]]],"list":[{"point":5,"width":50,"type_input":"","input_hint":["frac"],"ques":" S\u1ed1 ngh\u1ecbch \u0111\u1ea3o c\u1ee7a $\\dfrac{2}{7}$ l\u00e0: <div class=\"frac123\"><div class=\"ts\">_input_<\/div><div class=\"ms\">_input_<\/div><\/div>","hint":" S\u1ed1 ngh\u1ecbch \u0111\u1ea3o c\u1ee7a $\\dfrac{a}{b}$ l\u00e0 $\\dfrac{b}{a}$","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * S\u1ed1 ngh\u1ecbch \u0111\u1ea3o <\/b> <br\/> S\u1ed1 ngh\u1ecbch \u0111\u1ea3o c\u1ee7a $\\left( \\dfrac{a}{b} \\right)$ l\u00e0 $\\left( \\dfrac{a}{b} \\right)^ {-1}$ v\u00e0 $\\left( \\dfrac{a}{b} \\right)^ {-1} = \\dfrac{b}{a}.$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> S\u1ed1 ngh\u1ecbch \u0111\u1ea3o c\u1ee7a $\\dfrac{2}{7}$ l\u00e0 $\\dfrac{7}{2}$"}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"104","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" T\u00ecm $x \\in \\mathbb{Q}$ bi\u1ebft: $ \\dfrac{-7}{15} . x + \\dfrac{5}{6} = \\dfrac{1}{4} $ ","select":["A. $ x = \\dfrac{5}{4}$","B. $x = \\dfrac{-43}{28}$","C. $x = \\dfrac{-5}{4}$","D. $ x = \\dfrac{-7}{12} $"],"explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u00e0i to\u00e1n t\u00ecm x <\/b> <br\/> - Chuy\u1ec3n c\u00e1c h\u1ea1ng t\u1eed ch\u1ee9a x sang m\u1ed9t v\u1ebf, c\u00e1c h\u1eb1ng s\u1ed1 sang v\u1ebf kia. <br\/> - Thu g\u1ecdn v\u00e0 t\u00ecm x. <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $ \\dfrac{-7}{15} . x + \\dfrac{5}{6} = \\dfrac{1}{4} $<br\/>$\\Rightarrow \\dfrac{-7}{15} x = \\dfrac{1}{4} - \\dfrac{5}{6} $<br\/>$\\Rightarrow \\dfrac{-7}{15}x= \\dfrac{-7}{12} $<br\/>$\\Rightarrow x = \\dfrac{-7}{12} : \\dfrac{-7}{15} $<br\/>$\\Rightarrow x = \\dfrac{5}{4}$ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"105","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":" T\u00ecm $x \\in \\mathbb{Q}$ bi\u1ebft: $ \\dfrac{3}{4} + \\dfrac{1}{4} x = \\dfrac{2}{5} $ ","select":["A. $ x = \\dfrac{7}{20}$","B. $x = \\dfrac{-7}{20}$","C. $x = \\dfrac{-7}{5}$","D. $ x = \\dfrac{7}{5} $"],"hint":"Chuy\u1ec3n c\u00e1c h\u1ea1ng t\u1eed ch\u1ee9a x sang m\u1ed9t v\u1ebf, c\u00e1c h\u1eb1ng s\u1ed1 sang v\u1ebf kia. <br\/> - Thu g\u1ecdn v\u00e0 t\u00ecm x. ","explain":" $ \\dfrac{3}{4} + \\dfrac{1}{4} x = \\dfrac{2}{5} $<br\/>$\\Rightarrow \\dfrac{1}{4} x = \\dfrac{2}{5} - \\dfrac{3}{4} $<br\/>$\\Rightarrow \\dfrac{1}{4} x = \\dfrac{-7}{20} $<br\/>$\\Rightarrow x = \\dfrac{-7}{20} : \\dfrac{1}{4} $<br\/>$\\Rightarrow x = \\dfrac{-7}{5}$ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"106","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":" T\u00ecm $x \\in \\mathbb{Q}$ bi\u1ebft: $ \\dfrac{-2}{3} . x = \\dfrac{-16}{9}$ ","select":["A. $ x = \\dfrac{8}{9}$","B. $x = \\dfrac{1}{6}$","C. $x = \\dfrac{8}{3}$","D. $ x = \\dfrac{1}{3} $"],"explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> \u00c1p d\u1ee5ng: $a.x =b \\Rightarrow x = b: a $ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $\\dfrac{-2}{3} . x = \\dfrac{-16}{9} $<br\/>$\\Rightarrow x = \\dfrac{-16}{9} : \\left( \\dfrac{-2}{3} \\right) $<br\/>$\\Rightarrow x = \\dfrac{8}{3}$ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"107","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":" T\u00ecm $x \\in \\mathbb{Q}$ bi\u1ebft: $ \\dfrac{17}{8} . x = - \\dfrac{4}{5}$ ","select":["A. $ x = \\dfrac{-17}{10}$","B. $x = \\dfrac{-32}{85}$","C. $x = \\dfrac{-4}{17}$","D. $ x = \\dfrac{-32}{75} $"],"explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> \u00c1p d\u1ee5ng: $a.x =b \\Rightarrow x = b: a $<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $\\dfrac{17}{8} . x = - \\dfrac{4}{5} $ <br\/> $\\Rightarrow x = \\left( - \\dfrac{4}{5} \\right) : \\dfrac{17}{8} $ <br\/> $\\Rightarrow x = \\dfrac{-32}{85}$ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"108","post_id":"958","mon_id":"0","chapter_id":"0","question":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","options":{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["1"],["3"]]],"list":[{"point":5,"width":50,"content":"","type_input":"","input_hint":["frac"],"ques":" Vi\u1ebft k\u1ebft qu\u1ea3 c\u1ee7a bi\u1ec3u th\u1ee9c M v\u00e0o \u00f4 tr\u1ed1ng <br\/> $ M = \\dfrac{2}{3} + \\dfrac{3}{4} . \\left( \\dfrac{-4}{9} \\right) = $ <div class=\"frac123\"><div class=\"ts\">_input_<\/div><div class=\"ms\">_input_<\/div><\/div>","hint":"Th\u1ef1c hi\u1ec7n nh\u00e2n chia tr\u01b0\u1edbc c\u1ed9ng tr\u1eeb sau. ","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * Nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 <\/b> <br\/> \u0110\u1ec3 nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 x, y ta c\u00f3 th\u1ec3 vi\u1ebft ch\u00fang d\u01b0\u1edbi d\u1ea1ng hai ph\u00e2n s\u1ed1 r\u1ed3i \u00e1p d\u1ee5ng quy t\u1eafc nh\u00e2n, chia hai ph\u00e2n s\u1ed1, ngh\u0129a l\u00e0: <br\/> V\u1edbi $ x = \\dfrac{a}{b}, \\quad y = \\dfrac{c}{d} $ ta c\u00f3: $ \\qquad x.y = \\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d} $$\\qquad x:y = \\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a.d}{b.c}$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $ M = \\dfrac{2}{3} + \\dfrac{3}{4} . \\left( \\dfrac{-4}{9} \\right) $$ = \\dfrac{2}{3} + \\dfrac{3.(-4)}{4.9} $$= \\dfrac{2}{3} + \\dfrac{-12}{36} $$= \\dfrac{2}{3} + \\dfrac{-1}{3} = \\dfrac{1}{3}$ "}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"109","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"Ch\u1ecdn k\u1ebft qu\u1ea3 \u0111\u00fang c\u1ee7a bi\u1ec3u th\u1ee9c $ B = \\dfrac{-3}{4} . \\dfrac{12}{-5} . \\left( -\\dfrac{25}{6} \\right) $ ","select":["A. $ \\dfrac{15}{2}$","B. $\\dfrac{15}{6}$","C. $\\dfrac{-15}{2}$","D. $\\dfrac{9}{2}$"],"hint":"\u00c1p d\u1ee5ng quy t\u1eafc nh\u00e2n c\u00e1c ph\u00e2n s\u1ed1.","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * Nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 <\/b> <br\/> \u0110\u1ec3 nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 x, y ta c\u00f3 th\u1ec3 vi\u1ebft ch\u00fang d\u01b0\u1edbi d\u1ea1ng hai ph\u00e2n s\u1ed1 r\u1ed3i \u00e1p d\u1ee5ng quy t\u1eafc nh\u00e2n, chia hai ph\u00e2n s\u1ed1, ngh\u0129a l\u00e0: <br\/> V\u1edbi $ x = \\dfrac{a}{b}, \\quad y = \\dfrac{c}{d} $ ta c\u00f3: $ \\qquad x.y = \\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d} $$\\qquad x:y = \\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a.d}{b.c}$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $ B = \\dfrac{-3}{4} . \\dfrac{12}{-5} . \\left( -\\dfrac{25}{6} \\right) $$ = \\dfrac{-3}{4} . \\dfrac{-12}{5} . \\dfrac{-25}{6} $$= \\dfrac{(-3).(-12).(-25)}{4.5.6} $$= \\dfrac{-900}{120} = \\dfrac{-15}{2} $ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"110","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"Ch\u1ecdn k\u1ebft qu\u1ea3 \u0111\u00fang c\u1ee7a bi\u1ec3u th\u1ee9c $ A = (-5) . \\dfrac{-6}{13} . \\dfrac{-9}{10} $ ","select":["A. $ \\dfrac{-27}{13}$","B. $\\dfrac{27}{13}$","C. $\\dfrac{27}{130}$","D. $\\dfrac{-27}{130}$"],"hint":"\u00c1p d\u1ee5ng quy t\u1eafc nh\u00e2n c\u00e1c ph\u00e2n s\u1ed1.","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * Nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 <\/b> <br\/> \u0110\u1ec3 nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 x, y ta c\u00f3 th\u1ec3 vi\u1ebft ch\u00fang d\u01b0\u1edbi d\u1ea1ng hai ph\u00e2n s\u1ed1 r\u1ed3i \u00e1p d\u1ee5ng quy t\u1eafc nh\u00e2n, chia hai ph\u00e2n s\u1ed1, ngh\u0129a l\u00e0: <br\/> V\u1edbi $ x = \\dfrac{a}{b}, \\quad y = \\dfrac{c}{d} $ ta c\u00f3: $ \\qquad x.y = \\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d} $$\\qquad x:y = \\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a.d}{b.c}$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $ A = (-5) . \\dfrac{-6}{13} . \\dfrac{-9}{10} $$= \\dfrac{-5}{1} . \\dfrac{-6}{13} . \\dfrac{-9}{10} $$= \\dfrac{(-5).(-6).(-9)}{1.13.10} $$= \\dfrac{-270}{130} = \\dfrac{-27}{13} $ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"111","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":"Ch\u1ecdn k\u1ebft qu\u1ea3 \u0111\u00fang c\u1ee7a ph\u00e9p to\u00e1n $ \\dfrac{17}{18} : \\dfrac{51}{36} = ? $ ","select":["A. $ \\dfrac{17}{51}$","B. $\\dfrac{2}{51}$","C. $ \\dfrac{17}{3}$","D. $\\dfrac{2}{3}$"],"hint":" \u00c1p d\u1ee5ng quy t\u1eafc chia hai s\u1ed1 h\u1eefu t\u1ec9 $\\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a}{b} . \\dfrac{d}{c} = \\dfrac{a.d}{b.c}$","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * Nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 <\/b> <br\/> \u0110\u1ec3 nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 x, y ta c\u00f3 th\u1ec3 vi\u1ebft ch\u00fang d\u01b0\u1edbi d\u1ea1ng hai ph\u00e2n s\u1ed1 r\u1ed3i \u00e1p d\u1ee5ng quy t\u1eafc nh\u00e2n, chia hai ph\u00e2n s\u1ed1, ngh\u0129a l\u00e0: <br\/> V\u1edbi $ x = \\dfrac{a}{b}, \\quad y = \\dfrac{c}{d} $ ta c\u00f3: $ \\qquad x.y = \\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d} $$\\qquad x:y = \\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a.d}{b.c}$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $ \\dfrac{17}{18} : \\dfrac{51}{36} = \\dfrac{17}{18} . \\dfrac{36}{51} $$= \\dfrac{17.36}{18.51} = \\dfrac{17.18.2}{18.17.3} $$= \\dfrac{2}{3} $ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"112","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":"Ch\u1ecdn k\u1ebft qu\u1ea3 \u0111\u00fang c\u1ee7a ph\u00e9p to\u00e1n $ \\dfrac{9}{20} : (-18) = ? $ ","select":["A. $ \\dfrac{-1}{10}$","B. $\\dfrac{-1}{20}$","C. $ \\dfrac{-1}{30}$","D. $\\dfrac{-1}{40}$"],"hint":" \u00c1p d\u1ee5ng quy t\u1eafc chia hai s\u1ed1 h\u1eefu t\u1ec9 $\\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a}{b} . \\dfrac{d}{c} = \\dfrac{a.d}{b.c}$","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * Nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 <\/b> <br\/> \u0110\u1ec3 nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 x, y ta c\u00f3 th\u1ec3 vi\u1ebft ch\u00fang d\u01b0\u1edbi d\u1ea1ng hai ph\u00e2n s\u1ed1 r\u1ed3i \u00e1p d\u1ee5ng quy t\u1eafc nh\u00e2n, chia hai ph\u00e2n s\u1ed1, ngh\u0129a l\u00e0: <br\/> V\u1edbi $ x = \\dfrac{a}{b}, \\quad y = \\dfrac{c}{d} $ ta c\u00f3: $ \\qquad x.y = \\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d} $$\\qquad x:y = \\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a.d}{b.c}$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $ \\dfrac{9}{20} : (-18) = \\dfrac{9}{20} . \\dfrac{1}{-18} $$= \\dfrac{9.1}{20.(-18)} = \\dfrac{9}{-360} $$= \\dfrac{-1}{40} $ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"113","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"Ch\u1ecdn k\u1ebft qu\u1ea3 \u0111\u00fang c\u1ee7a ph\u00e9p to\u00e1n $ \\dfrac{11}{4} : \\dfrac{33}{16} = ? $ ","select":["A. $ \\dfrac{1}{3}$","B. $\\dfrac{4}{3}$","C. $ \\dfrac{2}{3}$","D. $\\dfrac{5}{3}$"],"hint":" \u00c1p d\u1ee5ng quy t\u1eafc chia hai s\u1ed1 h\u1eefu t\u1ec9 $\\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a}{b} . \\dfrac{d}{c} = \\dfrac{a.d}{b.c}$","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * Nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 <\/b> <br\/> \u0110\u1ec3 nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 x, y ta c\u00f3 th\u1ec3 vi\u1ebft ch\u00fang d\u01b0\u1edbi d\u1ea1ng hai ph\u00e2n s\u1ed1 r\u1ed3i \u00e1p d\u1ee5ng quy t\u1eafc nh\u00e2n, chia hai ph\u00e2n s\u1ed1, ngh\u0129a l\u00e0: <br\/> V\u1edbi $ x = \\dfrac{a}{b}, \\quad y = \\dfrac{c}{d} $ ta c\u00f3: $ \\qquad x.y = \\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d} $$\\qquad x:y = \\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a.d}{b.c}$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $ \\dfrac{11}{4} : \\dfrac{33}{16} = \\dfrac{11}{4} . \\dfrac{16}{33}$$ = \\dfrac{11.16}{4.33} = \\dfrac{11.4.4}{4.11.3} $$= \\dfrac{4}{3} $ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"114","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"Ch\u1ecdn k\u1ebft qu\u1ea3 \u0111\u00fang c\u1ee7a ph\u00e9p to\u00e1n $ \\dfrac{-5}{9} : \\dfrac{-7}{18} = ? $ ","select":["A. $ 1\\dfrac{3}{7}$","B. $\\dfrac{-10}{7}$","C. $ 2\\dfrac{3}{7}$","D. $\\dfrac{-3}{7}$"],"hint":" \u00c1p d\u1ee5ng quy t\u1eafc chia hai s\u1ed1 h\u1eefu t\u1ec9 $\\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a}{b} . \\dfrac{d}{c} = \\dfrac{a.d}{b.c}$","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * Nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 <\/b> <br\/> \u0110\u1ec3 nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 x, y ta c\u00f3 th\u1ec3 vi\u1ebft ch\u00fang d\u01b0\u1edbi d\u1ea1ng hai ph\u00e2n s\u1ed1 r\u1ed3i \u00e1p d\u1ee5ng quy t\u1eafc nh\u00e2n, chia hai ph\u00e2n s\u1ed1, ngh\u0129a l\u00e0: <br\/> V\u1edbi $ x = \\dfrac{a}{b}, \\quad y = \\dfrac{c}{d} $ ta c\u00f3: $ \\qquad x.y = \\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d} $$\\qquad x:y = \\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a.d}{b.c}$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $ \\dfrac{-5}{9} : \\dfrac{-7}{18} = \\dfrac{-5}{9} . \\dfrac{18}{-7} $$= \\dfrac{(-5).18}{9.(-7)} = \\dfrac{-90}{-63} $$= \\dfrac{10}{7} = 1\\dfrac{3}{7} $ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"115","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"Ch\u1ecdn k\u1ebft qu\u1ea3 \u0111\u00fang c\u1ee7a ph\u00e9p to\u00e1n $ \\dfrac{-5}{23} : (-2) = ? $ ","select":["A. $\\dfrac{10}{23}$","B. $\\dfrac{10}{46}$","C. $\\dfrac{5}{46}$","D. $\\dfrac{-5}{23}$"],"hint":" \u00c1p d\u1ee5ng quy t\u1eafc chia hai s\u1ed1 h\u1eefu t\u1ec9 $\\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a}{b} . \\dfrac{d}{c} = \\dfrac{a.d}{b.c}$","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * Nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 <\/b> <br\/> \u0110\u1ec3 nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 x, y ta c\u00f3 th\u1ec3 vi\u1ebft ch\u00fang d\u01b0\u1edbi d\u1ea1ng hai ph\u00e2n s\u1ed1 r\u1ed3i \u00e1p d\u1ee5ng quy t\u1eafc nh\u00e2n, chia hai ph\u00e2n s\u1ed1, ngh\u0129a l\u00e0: <br\/> V\u1edbi $ x = \\dfrac{a}{b}, \\quad y = \\dfrac{c}{d} $ ta c\u00f3: $ \\qquad x.y = \\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d} $$\\qquad x:y = \\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a.d}{b.c}$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $ \\dfrac{-5}{23} : (-2) = \\dfrac{-5}{23} . \\dfrac{1}{-2}$$ = \\dfrac{(-5).1}{23.(-2)} = \\dfrac{-5}{-46} $$= \\dfrac{5}{46} $ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"116","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"Ch\u1ecdn k\u1ebft qu\u1ea3 \u0111\u00fang c\u1ee7a ph\u00e9p to\u00e1n $ (-2) . \\left( \\dfrac{-7}{12} \\right) = ? $ ","select":["A. $ \\dfrac{-7}{6}$","B. $\\dfrac{7}{6}$","C. $\\dfrac{3}{4}$","D. $2\\dfrac{-3}{4}$"],"hint":" \u00c1p d\u1ee5ng quy t\u1eafc nh\u00e2n hai s\u1ed1 h\u1eefu t\u1ec9 $\\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d}$","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * Nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 <\/b> <br\/> \u0110\u1ec3 nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 x, y ta c\u00f3 th\u1ec3 vi\u1ebft ch\u00fang d\u01b0\u1edbi d\u1ea1ng hai ph\u00e2n s\u1ed1 r\u1ed3i \u00e1p d\u1ee5ng quy t\u1eafc nh\u00e2n, chia hai ph\u00e2n s\u1ed1, ngh\u0129a l\u00e0: <br\/> V\u1edbi $ x = \\dfrac{a}{b}, \\quad y = \\dfrac{c}{d} $ ta c\u00f3: $ \\qquad x.y = \\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d} $$\\qquad x:y = \\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a.d}{b.c}$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $ (-2) . \\left( \\dfrac{-7}{12} \\right) = \\dfrac{-2}{1} . \\dfrac{-7}{12} $$= \\dfrac{(-2)(-7)}{1.12}= \\dfrac{14}{12} $$= \\dfrac{7}{6} $ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"117","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"Ch\u1ecdn k\u1ebft qu\u1ea3 \u0111\u00fang c\u1ee7a ph\u00e9p to\u00e1n $ \\dfrac{-7}{4} . \\dfrac{8}{5} = ? $ ","select":["A. $ -1$","B. $\\dfrac{9}{5}$","C. $\\dfrac{-14}{5}$","D. $2\\dfrac{4}{5}$"],"hint":" \u00c1p d\u1ee5ng quy t\u1eafc nh\u00e2n hai s\u1ed1 h\u1eefu t\u1ec9 $\\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d}$","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * Nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 <\/b> <br\/> \u0110\u1ec3 nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 x, y ta c\u00f3 th\u1ec3 vi\u1ebft ch\u00fang d\u01b0\u1edbi d\u1ea1ng hai ph\u00e2n s\u1ed1 r\u1ed3i \u00e1p d\u1ee5ng quy t\u1eafc nh\u00e2n, chia hai ph\u00e2n s\u1ed1, ngh\u0129a l\u00e0: <br\/> V\u1edbi $ x = \\dfrac{a}{b}, \\quad y = \\dfrac{c}{d} $ ta c\u00f3: $ \\qquad x.y = \\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d} $$\\qquad x:y = \\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a.d}{b.c}$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $ \\dfrac{-7}{4} . \\dfrac{8}{5} = \\dfrac{(-7).8}{4.5}$$ = \\dfrac{-56}{20}= \\dfrac{-14}{5}$ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"118","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"Ch\u1ecdn k\u1ebft qu\u1ea3 \u0111\u00fang c\u1ee7a ph\u00e9p to\u00e1n $ 2\\dfrac{3}{11} . \\dfrac{1}{12} = ? $ ","select":["A. $ \\dfrac{25}{121}$","B. $\\dfrac{25}{132}$","C. $\\dfrac{22}{132}$","D. $\\dfrac{19}{132}$"],"hint":" \u00c1p d\u1ee5ng quy t\u1eafc nh\u00e2n hai s\u1ed1 h\u1eefu t\u1ec9 $\\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d}$","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * Nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 <\/b> <br\/> \u0110\u1ec3 nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 x, y ta c\u00f3 th\u1ec3 vi\u1ebft ch\u00fang d\u01b0\u1edbi d\u1ea1ng hai ph\u00e2n s\u1ed1 r\u1ed3i \u00e1p d\u1ee5ng quy t\u1eafc nh\u00e2n, chia hai ph\u00e2n s\u1ed1, ngh\u0129a l\u00e0: <br\/> V\u1edbi $ x = \\dfrac{a}{b}, \\quad y = \\dfrac{c}{d} $ ta c\u00f3: $ \\qquad x.y = \\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d} $$\\qquad x:y = \\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a.d}{b.c}$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $ 2\\dfrac{3}{11} . \\dfrac{1}{12} $$= \\dfrac{25}{11} . \\dfrac{1}{12} = \\dfrac{25.1}{11.12} $$= \\dfrac{25}{132}$ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"119","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"Ch\u1ecdn k\u1ebft qu\u1ea3 \u0111\u00fang c\u1ee7a ph\u00e9p to\u00e1n $ \\dfrac{-3}{11} . \\dfrac{33}{10} = ? $ ","select":["A. $ \\dfrac{-9}{10}$","B. $\\dfrac{99}{110}$","C. $\\dfrac{-3}{11}$","D. $\\dfrac{9}{10}$"],"hint":" \u00c1p d\u1ee5ng quy t\u1eafc nh\u00e2n hai s\u1ed1 h\u1eefu t\u1ec9 $\\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d}$","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * Nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 <\/b> <br\/> \u0110\u1ec3 nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 x, y ta c\u00f3 th\u1ec3 vi\u1ebft ch\u00fang d\u01b0\u1edbi d\u1ea1ng hai ph\u00e2n s\u1ed1 r\u1ed3i \u00e1p d\u1ee5ng quy t\u1eafc nh\u00e2n, chia hai ph\u00e2n s\u1ed1, ngh\u0129a l\u00e0: <br\/> V\u1edbi $ x = \\dfrac{a}{b}, \\quad y = \\dfrac{c}{d} $ ta c\u00f3: $ \\qquad x.y = \\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d} $$\\qquad x:y = \\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a.d}{b.c}$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $ \\dfrac{-3}{11} . \\dfrac{33}{10} = \\dfrac{(-3).33}{11.10} $$ = \\dfrac{(-3).3}{1.10} = \\dfrac{-9}{10} $ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"},{"id":"120","post_id":"958","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"Ch\u1ecdn k\u1ebft qu\u1ea3 \u0111\u00fang c\u1ee7a ph\u00e9p to\u00e1n $ 0,5 . \\dfrac{-15}{4} = ? $ ","select":["A. $ \\dfrac{-15}{8}$","B. $\\dfrac{-75}{8}$","C. $\\dfrac{15}{8}$","D. $\\dfrac{75}{8}$"],"hint":" \u00c1p d\u1ee5ng quy t\u1eafc nh\u00e2n hai s\u1ed1 h\u1eefu t\u1ec9 $\\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d}$","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> * Nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 <\/b> <br\/> \u0110\u1ec3 nh\u00e2n, chia hai s\u1ed1 h\u1eefu t\u1ec9 x, y ta c\u00f3 th\u1ec3 vi\u1ebft ch\u00fang d\u01b0\u1edbi d\u1ea1ng hai ph\u00e2n s\u1ed1 r\u1ed3i \u00e1p d\u1ee5ng quy t\u1eafc nh\u00e2n, chia hai ph\u00e2n s\u1ed1, ngh\u0129a l\u00e0: <br\/> V\u1edbi $ x = \\dfrac{a}{b}, \\quad y = \\dfrac{c}{d} $ ta c\u00f3: $ \\qquad x.y = \\dfrac{a}{b} . \\dfrac{c}{d} = \\dfrac{a.c}{b.d} $$\\qquad x:y = \\dfrac{a}{b} : \\dfrac{c}{d} = \\dfrac{a.d}{b.c}$ <\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> $ 0,5 . \\dfrac{-15}{4} = \\dfrac{5}{10} . \\dfrac{-15}{4} $$= \\dfrac{1}{2} . \\dfrac{-15}{4} = \\dfrac{1.(-15)}{2.4} $$= \\dfrac{-15}{8} $ <br\/> <br\/> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> <br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:43"}]}