{"segment":[{"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":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/daiso/bai6/lv2/img\/9.jpg' \/><\/center>So s\u00e1nh hai s\u1ed1 h\u1eefu t\u1ec9 $\\dfrac{76}{-89}$ v\u00e0 $\\dfrac{-5}{9}$ b\u1eb1ng c\u00e1ch nh\u00e2n ch\u00e9o ta \u0111\u01b0\u1ee3c: ","select":["A. $\\dfrac{76}{-89}$ < $\\dfrac{-5}{9}$ ","B. $\\dfrac{76}{-89}$ = $\\dfrac{-5}{9}$ ","C. $\\dfrac{76}{-89}$ > $\\dfrac{-5}{9}$"],"explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span> <br\/> $\\bullet $ <b> So s\u00e1nh hai s\u1ed1 h\u1eefu t\u1ec9 b\u1eb1ng c\u00e1ch nh\u00e2n ch\u00e9o: <\/b> <br\/> So s\u00e1nh $\\dfrac{a}{b}$ v\u00e0 $\\dfrac{c}{d}$ v\u1edbi $bd > 0 $ <br\/> * N\u1ebfu t\u00edch $ad > bc$ th\u00ec $\\dfrac{a}{b} > \\dfrac{c}{d}$ <br\/> * N\u1ebfu t\u00edch $ad < bc$ th\u00ec $\\dfrac{a}{b} < \\dfrac{c}{d}$ <\/span> <br\/> <br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> Vi\u1ebft l\u1ea1i t\u1ec9 s\u1ed1 $\\dfrac{76}{-89} = \\dfrac{-76}{89}$ <br\/> Ta ph\u1ea3i so s\u00e1nh $\\dfrac{-76}{89}$ v\u00e0 $\\dfrac{-5}{9}$ <br\/> C\u00f3: $(-76) . 9 = -684 $ v\u00e0 $89 . (-5) = -445 $ <br\/> M\u00e0 $-684 < -445$ suy ra $\\dfrac{-76}{89} < \\dfrac{-5}{9}$ <br\/> Hay $\\dfrac{76}{-89} < \\dfrac{-5}{9} $ <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n c\u1ea7n ch\u1ecdn l\u00e0 A. <\/span><\/span> ","column":3}]}],"id_ques":271},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["121"],["2"]]],"list":[{"point":5,"width":50,"type_input":"","ques":" T\u00ecm $x$ trong t\u1ec9 l\u1ec7 th\u1ee9c: $ \\dfrac{52}{2x-1} = \\dfrac{13}{30} $ <br\/> <b> \u0110\u00e1p s\u1ed1: <\/b> $ x$ = <div class=\"frac123\"><div class=\"ts\">_input_<\/div><div class=\"ms\">_input_<\/div><\/div>","explain":" \u00c1p d\u1ee5ng t\u00ednh ch\u1ea5t c\u1ee7a t\u1ec9 l\u1ec7 th\u1ee9c ta c\u00f3: <br\/> $ \\dfrac{52}{2x-1} = \\dfrac{13}{30} \\\\ \\Rightarrow 2x - 1 = \\dfrac{52.30}{13} = \\dfrac{1560}{13} = 120 \\\\ \\Rightarrow 2x = 120 + 1 = 121 \\\\ \\Rightarrow x = 121 : 2 = \\dfrac{121}{2} $ <br\/> <br\/> <span class='basic_pink'> V\u1eady gi\u00e1 tr\u1ecb c\u1ee7a $x$ l\u00e0 $ \\dfrac{121}{2} $ <\/span><\/span>"}]}],"id_ques":272},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["-4"]]],"list":[{"point":5,"width":50,"type_input":"","ques":" T\u00ecm $x$ trong t\u1ec9 l\u1ec7 th\u1ee9c: $ \\dfrac{x+3}{-4} = \\dfrac{5}{20}?$ <br\/> <b> \u0110\u00e1p s\u1ed1: <\/b> $ x = $ _input_","explain":" \u00c1p d\u1ee5ng t\u00ednh ch\u1ea5t c\u1ee7a t\u1ec9 l\u1ec7 th\u1ee9c ta c\u00f3: <br\/> $ \\dfrac{x+3}{-4} = \\dfrac{5}{20} \\\\ \\Rightarrow x + 3 = \\dfrac{(-4).5}{20} = -1 \\\\ \\Rightarrow x = -1 - 3 = -4 $ <br\/> <br\/> <span class='basic_pink'> V\u1eady gi\u00e1 tr\u1ecb c\u1ee7a $x$ l\u00e0 $ -4 $ <\/span><\/span>"}]}],"id_ques":273},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["0,512"]]],"list":[{"point":5,"width":100,"type_input":"","ques":" \u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng d\u01b0\u1edbi \u0111\u00e2y \u0111\u1ec3 c\u00f3 t\u1ec9 l\u1ec7 th\u1ee9c: <br\/> <br\/>$\\dfrac{-16}{3} : $ _input_ = \\dfrac{25}{6} : (-0,4) $ <br\/> (Vi\u1ebft k\u1ebft qu\u1ea3 d\u01b0\u1edbi d\u1ea1ng s\u1ed1 th\u1eadp ph\u00e2n) ","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> \u00c1p d\u1ee5ng t\u00ednh ch\u1ea5t: $a : b = c : d \\Rightarrow b = ad : c $ <\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> G\u1ecdi s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u00e0 x <br\/> $ \\dfrac{-16}{3} : x = \\dfrac{25}{6} : (-0,4) \\\\ \\Rightarrow \\dfrac{-16}{3} : x = \\dfrac{-125}{12} \\\\ \\Rightarrow x = \\dfrac{-16}{3} : \\dfrac{-125}{12} \\\\ \\Rightarrow x = \\dfrac{64}{125} = 0,512 $ <br\/> <br\/> <span class='basic_pink'> K\u1ebft qu\u1ea3 ph\u1ea3i \u0111i\u1ec1n l\u00e0 $0,512 $ <\/span><\/span>"}]}],"id_ques":274},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["5"],["4"]]],"list":[{"point":5,"width":50,"type_input":"","ques":" T\u00ecm $x$ trong t\u1ec9 l\u1ec7 th\u1ee9c: $ \\dfrac{\\dfrac{-1}{2}}{2x-1} = \\dfrac{0,2}{\\dfrac{-3}{5}}? $ <br\/> <b> \u0110\u00e1p s\u1ed1: <\/b>$ x $= <div class=\"frac123\"><div class=\"ts\">_input_<\/div><div class=\"ms\">_input_<\/div><\/div>","explain":" \u00c1p d\u1ee5ng t\u00ednh ch\u1ea5t c\u1ee7a t\u1ec9 l\u1ec7 th\u1ee9c ta c\u00f3: <br\/> $ \\dfrac{\\dfrac{-1}{2}}{2x-1} = \\dfrac{0,2}{\\dfrac{-3}{5}} \\\\ \\Rightarrow (2x -1).0,2 = \\dfrac{-1}{2}.\\dfrac{-3}{5} \\\\ \\Rightarrow (2x -1).\\dfrac{1}{5} = \\dfrac{3}{10} \\\\ \\Rightarrow 2x - 1 = \\dfrac{3}{10} : \\dfrac{1}{5} \\\\ \\Rightarrow 2x - 1 = \\dfrac{3}{2} \\\\ \\Rightarrow 2x = \\dfrac{5}{2} \\\\ \\Rightarrow x = \\dfrac{5}{4}$ <br\/> <br\/> <span class='basic_pink'> V\u1eady gi\u00e1 tr\u1ecb c\u1ee7a $x$ l\u00e0 $ \\dfrac{5}{4} $ <\/span><\/span>"}]}],"id_ques":275},{"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":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/daiso/bai6/lv2/img\/9.jpg' \/><\/center> T\u00ecm $x$ trong t\u1ec9 l\u1ec7 th\u1ee9c sau: $ \\dfrac{-2,6}{x} = \\dfrac{-12}{42}?$ ","select":["A. $ x = -9,1 $ ","B. $ x = 9,1 $ ","C. $ x = 18,2 $ ","D. $ x = -18,2 $ "],"explain":" \u00c1p d\u1ee5ng t\u00ednh ch\u1ea5t c\u1ee7a t\u1ec9 l\u1ec7 th\u1ee9c ta c\u00f3: <br\/> $ \\dfrac{-2,6}{x} = \\dfrac{-12}{42} \\Rightarrow x = \\dfrac{-2,6 . 42}{-12} = 9,1$ <br\/> V\u1eady gi\u00e1 tr\u1ecb c\u1ee7a $x$ l\u00e0 $ 9,1 $ <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span><\/span>","column":2}]}],"id_ques":276},{"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":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/daiso/bai6/lv2/img\/9.jpg' \/><\/center> Cho t\u1ec9 l\u1ec7 th\u1ee9c $\\dfrac{-3}{21} = \\dfrac{-4,2}{29,4}.$ <Kh\u1eb3ng \u0111\u1ecbnh \u0111\u00fang l\u00e0: ","select":["A. C\u00e1c s\u1ed1 $-3$ v\u00e0 $-4,2$ l\u00e0 c\u00e1c s\u1ed1 ngo\u1ea1i t\u1ec9. ","B. C\u00e1c s\u1ed1 $-3$ v\u00e0 $29,4$ l\u00e0 c\u00e1c s\u1ed1 ngo\u1ea1i t\u1ec9.","C. C\u00e1c s\u1ed1 $-3$ v\u00e0 $-4,2$ l\u00e0 c\u00e1c s\u1ed1 trung t\u1ec9. ","D. C\u00e1c s\u1ed1 $21$ v\u00e0 $29,4$ l\u00e0 c\u00e1c s\u1ed1 trung t\u1ec9."],"explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span> <br\/> <b> \u0110\u1ecbnh ngh\u0129a :<\/b> <br\/> T\u1ec9 l\u1ec7 th\u1ee9c l\u00e0 \u0111\u1eb3ng th\u1ee9c c\u1ee7a hai t\u1ec9 s\u1ed1. <br\/> D\u1ea1ng t\u1ed5ng qu\u00e1t: $\\dfrac{a}{b} = \\dfrac{c}{d}$ ho\u1eb7c $a : b = c : d (a, b, c, d \\in \\mathbb{Q}; b \\neq 0; d \\neq 0)$ <br\/> C\u00e1c s\u1ed1 $a$ v\u00e0 $d$ g\u1ecdi l\u00e0 ngo\u1ea1i t\u1ec9; c\u00e1c s\u1ed1 $b$ v\u00e0 $c$ g\u1ecdi l\u00e0 trung t\u1ec9. <\/span> <br\/> <br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> Theo \u0111\u1ecbnh ngh\u0129a c\u1ee7a t\u1ec9 l\u1ec7 th\u1ee9c ta c\u00f3: <br\/> C\u00e1c s\u1ed1 $-3$ v\u00e0 $29,4$ l\u00e0 c\u00e1c s\u1ed1 ngo\u1ea1i t\u1ec9. <br\/> C\u00e1c s\u1ed1 $-4,2$ v\u00e0 $21$ l\u00e0 c\u00e1c s\u1ed1 trung t\u1ec9. <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span><\/span> ","column":2}]}],"id_ques":277},{"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":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/daiso/bai6/lv2/img\/9.jpg' \/><\/center> Cho t\u1ec9 l\u1ec7 th\u1ee9c $\\dfrac{2,4}{6} = \\dfrac{5,4}{13,5}.$ Kh\u1eb3ng \u0111\u1ecbnh \u0111\u00fang l\u00e0: ","select":["A. C\u00e1c s\u1ed1 $2,4$ v\u00e0 $5,4$ l\u00e0 c\u00e1c s\u1ed1 ngo\u1ea1i t\u1ec9. ","B. C\u00e1c s\u1ed1 $5,4$ v\u00e0 $13,5$ l\u00e0 c\u00e1c s\u1ed1 ngo\u1ea1i t\u1ec9.","C. C\u00e1c s\u1ed1 $6$ v\u00e0 $5,4$ l\u00e0 c\u00e1c s\u1ed1 trung t\u1ec9. ","D. C\u00e1c s\u1ed1 $13,5$ v\u00e0 $6$ l\u00e0 c\u00e1c s\u1ed1 trung t\u1ec9."],"explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span> <br\/> <b> \u0110\u1ecbnh ngh\u0129a :<\/b> <br\/> T\u1ec9 l\u1ec7 th\u1ee9c l\u00e0 \u0111\u1eb3ng th\u1ee9c c\u1ee7a hai t\u1ec9 s\u1ed1. <br\/> D\u1ea1ng t\u1ed5ng qu\u00e1t: $\\dfrac{a}{b} = \\dfrac{c}{d}$ ho\u1eb7c $a : b = c : d (a, b, c, d \\in \\mathbb{Q}; b \\neq 0; d \\neq 0)$ <br\/> C\u00e1c s\u1ed1 $a$ v\u00e0 $d$ g\u1ecdi l\u00e0 ngo\u1ea1i t\u1ec9; c\u00e1c s\u1ed1 $b$ v\u00e0 $c$ g\u1ecdi l\u00e0 trung t\u1ec9. <\/span> <br\/> <br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> Theo \u0111\u1ecbnh ngh\u0129a c\u1ee7a t\u1ec9 l\u1ec7 th\u1ee9c ta c\u00f3: <br\/> C\u00e1c s\u1ed1 $2,4$ v\u00e0 $13,5$ l\u00e0 c\u00e1c s\u1ed1 ngo\u1ea1i t\u1ec9. <br\/> C\u00e1c s\u1ed1 $5,4$ v\u00e0 $6$ l\u00e0 c\u00e1c s\u1ed1 trung t\u1ec9. <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C <\/span><\/span> ","column":2}]}],"id_ques":278},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["37"],["45"]]],"list":[{"point":5,"width":50,"type_input":"","ques":" Thay t\u1ec9 s\u1ed1 gi\u1eefa hai s\u1ed1 h\u1eefu t\u1ec9 b\u1eb1ng t\u1ec9 s\u1ed1 gi\u1eefa hai s\u1ed1 nguy\u00ean: <br\/> 3,7 : 4,5 = _input_ : _input_<br\/> (c\u00e1c s\u1ed1 h\u1ea1ng \u1edf d\u1ea1ng t\u1ed1i gi\u1ea3n) ","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> Thay t\u1ec9 s\u1ed1 gi\u1eefa c\u00e1c s\u1ed1 h\u1eefu t\u1ec9 b\u1eb1ng t\u1ec9 s\u1ed1 gi\u1eefa c\u00e1c s\u1ed1 nguy\u00ean <\/b> <br\/> <i> <u> Ph\u01b0\u01a1ng ph\u00e1p gi\u1ea3i: <\/i> <\/u> <br\/> $\\bullet$ Vi\u1ebft c\u00e1c s\u1ed1 h\u1eefu t\u1ec9 d\u01b0\u1edbi d\u1ea1ng ph\u00e2n s\u1ed1.<br\/> $\\bullet$ Th\u1ef1c hi\u1ec7n ph\u00e9p chia ph\u00e2n s\u1ed1. <\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> $ 3,7 : 4,5 = \\dfrac{37}{10} : \\dfrac{45}{10}$$ = \\dfrac{37}{10}.\\dfrac{10}{45} $$= \\dfrac{37}{45}$ <br\/> Suy ra ta c\u00f3 t\u1ec9 s\u1ed1: $ 3,7 : 4,5 = 37 : 45 $ <br\/> <br\/> <span class='basic_pink'> K\u1ebft qu\u1ea3 l\u00e0 $37 : 45$ <\/span><\/span>"}]}],"id_ques":279},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["44"],["15"]]],"list":[{"point":5,"width":50,"type_input":"","ques":" Thay t\u1ec9 s\u1ed1 gi\u1eefa hai s\u1ed1 h\u1eefu t\u1ec9 b\u1eb1ng t\u1ec9 s\u1ed1 gi\u1eefa hai s\u1ed1 nguy\u00ean: <br\/> <br\/> $ 2\\dfrac{1}{5} : \\dfrac{3}{4} = $_input_ : _input_<br\/> (c\u00e1c s\u1ed1 h\u1ea1ng \u1edf d\u1ea1ng t\u1ed1i gi\u1ea3n) ","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> Thay t\u1ec9 s\u1ed1 gi\u1eefa c\u00e1c s\u1ed1 h\u1eefu t\u1ec9 b\u1eb1ng t\u1ec9 s\u1ed1 gi\u1eefa c\u00e1c s\u1ed1 nguy\u00ean <\/b> <br\/> <i> <u> Ph\u01b0\u01a1ng ph\u00e1p gi\u1ea3i: <\/i> <\/u> <br\/> $\\bullet$ Vi\u1ebft c\u00e1c s\u1ed1 h\u1eefu t\u1ec9 d\u01b0\u1edbi d\u1ea1ng ph\u00e2n s\u1ed1.<br\/> $\\bullet$ Th\u1ef1c hi\u1ec7n ph\u00e9p chia ph\u00e2n s\u1ed1. <\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> $ 2\\dfrac{1}{5} : \\dfrac{3}{4} = \\dfrac{11}{5} : \\dfrac{3}{4}$$ = \\dfrac{11}{5} . \\dfrac{4}{3} $$= \\dfrac{44}{15} $ <br\/> Suy ra ta c\u00f3 t\u1ec9 s\u1ed1: $ 2\\dfrac{1}{5} : \\dfrac{3}{4} = 44 : 15 $ <br\/> <br\/> <span class='basic_pink'> K\u1ebft qu\u1ea3 l\u00e0 $44 : 15$ <\/span><\/span>"}]}],"id_ques":280},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["25"],["36"]]],"list":[{"point":5,"width":50,"type_input":"","ques":" Thay t\u1ec9 s\u1ed1 gi\u1eefa hai s\u1ed1 h\u1eefu t\u1ec9 b\u1eb1ng t\u1ec9 s\u1ed1 gi\u1eefa hai s\u1ed1 nguy\u00ean: <br\/> <br\/> 1,5 : 2,16 = _input_ : _input_<br\/> (c\u00e1c s\u1ed1 h\u1ea1ng \u1edf d\u1ea1ng t\u1ed1i gi\u1ea3n) ","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> Thay t\u1ec9 s\u1ed1 gi\u1eefa c\u00e1c s\u1ed1 h\u1eefu t\u1ec9 b\u1eb1ng t\u1ec9 s\u1ed1 gi\u1eefa c\u00e1c s\u1ed1 nguy\u00ean <\/b> <br\/> <i> <u> Ph\u01b0\u01a1ng ph\u00e1p gi\u1ea3i: <\/i> <\/u> <br\/> $\\bullet$ Vi\u1ebft c\u00e1c s\u1ed1 h\u1eefu t\u1ec9 d\u01b0\u1edbi d\u1ea1ng ph\u00e2n s\u1ed1.<br\/> $\\bullet$ Th\u1ef1c hi\u1ec7n ph\u00e9p chia ph\u00e2n s\u1ed1. <\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> $ 1,5 : 2,16 = \\dfrac{15}{10} : \\dfrac{216}{100} = \\dfrac{15}{10} . \\dfrac{100}{216} = \\dfrac{150}{216} = \\dfrac{25}{36} $ <br\/> Suy ra ta c\u00f3 t\u1ec9 s\u1ed1: $ 1,5 : 2,16 = 25 : 36 $ <br\/> <br\/> <span class='basic_pink'> K\u1ebft qu\u1ea3 l\u00e0 $25 : 36$ <\/span><\/span>"}]}],"id_ques":281},{"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":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/daiso/bai6/lv2/img\/9.jpg' \/><\/center> T\u00ecm $x$ trong t\u1ec9 l\u1ec7 th\u1ee9c sau: $ 3,8 : 2x = \\dfrac{1}{4} : 2\\dfrac{2}{3}?$ ","select":["A. $x = \\dfrac{15}{304} $ ","B. $x = \\dfrac{57}{320}$ ","C. $x = 20\\dfrac{4}{15}$ ","D. $x = \\dfrac{10}{247}$ "],"explain":" \u00c1p d\u1ee5ng t\u00ednh ch\u1ea5t c\u1ee7a t\u1ec9 l\u1ec7 th\u1ee9c ta c\u00f3: <br\/> $3,8 : 2x = \\dfrac{1}{4} : 2\\dfrac{2}{3} \\\\ \\Rightarrow 2x = \\left(3,8 . 2\\dfrac{2}{3}\\right) : \\dfrac{1}{4} \\\\ \\Rightarrow 2x = \\left(\\dfrac{19}{5} . \\dfrac{8}{3}\\right).4 \\\\ \\Rightarrow 2x = \\dfrac{608}{15} \\\\ \\Rightarrow x = \\dfrac{608}{15} : 2 \\\\ \\Rightarrow x = \\dfrac{304}{15} = 20\\dfrac{4}{15} $ <br\/> V\u1eady gi\u00e1 tr\u1ecb c\u1ee7a x l\u00e0 $ 20\\dfrac{4}{15} $ <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C. <\/span><\/span>","column":2}]}],"id_ques":282},{"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":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/daiso/bai6/lv2/img\/8.jpg' \/><\/center> T\u00ecm $x$ trong t\u1ec9 l\u1ec7 th\u1ee9c: $ (0,25x) : 3 = \\dfrac{5}{6} : 0,125 ?$ ","select":["A. $x = 0,125 $ ","B. $x = 80$ ","C. $x = \\dfrac{20}{3}$ ","D. $x = 8\\dfrac{8}{9}$"],"explain":" \u00c1p d\u1ee5ng t\u00ednh ch\u1ea5t c\u1ee7a t\u1ec9 l\u1ec7 th\u1ee9c ta c\u00f3: <br\/> $ (0,25x) : 3 = \\dfrac{5}{6} : 0,125 \\\\ \\Rightarrow 0,25x = \\left(3 . \\dfrac{5}{6}\\right) : 0,125 \\\\ \\Rightarrow 0,25x =\\dfrac{5}{2}.8 \\\\ \\Rightarrow 0,25x = 20 \\\\ \\Rightarrow x = 20 : 0,25 = 80 $ <br\/> V\u1eady gi\u00e1 tr\u1ecb c\u1ee7a x l\u00e0 $ 80 $ <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B <\/span><\/span>","column":2}]}],"id_ques":283},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["7"],["2"]]],"list":[{"point":5,"width":50,"type_input":"","ques":" \u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng d\u01b0\u1edbi \u0111\u00e2y \u0111\u1ec3 c\u00f3 t\u1ec9 l\u1ec7 th\u1ee9c: <br\/> <br\/> $\\dfrac{1}{2}$ : <div class=\"frac123\"><div class=\"ts\">_input_<\/div><div class=\"ms\">_input_<\/div><\/div> = $\\dfrac{3}{4} : 5\\dfrac{1}{4} $ ","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> \u00c1p d\u1ee5ng t\u00ednh ch\u1ea5t: $a : b = c : d \\Rightarrow b = ad : c $ <\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> G\u1ecdi s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u00e0 x <br\/> $ \\dfrac{1}{2} : x = \\dfrac{3}{4} : 5\\dfrac{1}{4} \\\\ \\Rightarrow x = \\left( \\dfrac{1}{2} . 5\\dfrac{1}{4} \\right) : \\dfrac{3}{4} \\\\ \\Rightarrow x = \\dfrac{21}{8} : \\dfrac{3}{4}\\\\ \\Rightarrow x = \\dfrac{7}{2} $ <br\/> <br\/> <span class='basic_pink'> V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u00e0 $ \\dfrac{7}{2} $ <\/span><\/span>"}]}],"id_ques":284},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["3"]]],"list":[{"point":5,"width":50,"type_input":"","ques":" \u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng d\u01b0\u1edbi \u0111\u00e2y \u0111\u1ec3 c\u00f3 t\u1ec9 l\u1ec7 th\u1ee9c:<div class=\"frac123\"><div class=\"ts\">_input_<\/div><div class=\"ms\">2,7<\/div><\/div> = \\dfrac{0,7}{0,63} $ ","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> \u00c1p d\u1ee5ng t\u00ednh ch\u1ea5t: $\\dfrac{a}{b} = \\dfrac{c}{d} \\Rightarrow a = \\dfrac{b.c}{d} $ <\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> G\u1ecdi s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u00e0 x <br\/> $\\dfrac{x}{2,7} = \\dfrac{0,7}{0,63} \\\\ \\Rightarrow x = \\dfrac{2,7.0,7}{0,63} = 3 $ <br\/> Suy ra ta c\u00f3 t\u1ec9 l\u1ec7 th\u1ee9c $ \\dfrac{3}{2,7} = \\dfrac{0,7}{0,63} $ <br\/> <br\/> <span class='basic_pink'> K\u1ebft qu\u1ea3 ph\u1ea3i \u0111i\u1ec1n l\u00e0 $3 $ <\/span><\/span>"}]}],"id_ques":285},{"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":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/daiso/bai6/lv2/img\/8.jpg' \/><\/center> N\u1ebfu $ ab = cd , (a, b, c, d \\neq 0)$ th\u00ec: ","select":["A. $ \\dfrac{a}{b} = \\dfrac{c}{d} $ ","B. $ \\dfrac{a}{d} = \\dfrac{c}{b} $ ","C. $ \\dfrac{a}{c} = \\dfrac{b}{d} $","D. $ \\dfrac{b}{c} = \\dfrac{a}{d} $"],"explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span> <br\/> * N\u1ebfu $ad = bc$ v\u00e0 $a, b, c, d \\neq 0$ th\u00ec ta c\u00f3 c\u00e1c t\u1ec9 l\u1ec7 th\u1ee9c: <br\/> $\\dfrac{a}{b} = \\dfrac{c}{d} \\Rightarrow \\dfrac{a}{c} = \\dfrac{b}{d} \\Rightarrow \\dfrac{d}{b} = \\dfrac{c}{a} \\Rightarrow \\dfrac{d}{c} = \\dfrac{b}{a}$ <\/span> <br\/> <br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> Theo t\u00ednh ch\u1ea5t c\u1ee7a t\u1ec9 l\u1ec7 th\u1ee9c ta c\u00f3: <br\/> $A.\\dfrac{a}{b} = \\dfrac{c}{d} \\Rightarrow ad = bc$ (lo\u1ea1i)<br\/> $B. \\dfrac{a}{d} = \\dfrac{c}{b} \\Rightarrow ab = cd $ (th\u1ecfa m\u00e3n)<br\/> $ C. \\dfrac{a}{c} = \\dfrac{b}{d} \\Rightarrow ad = bc $ (lo\u1ea1i) <br\/> $ D. \\dfrac{b}{c} = \\dfrac{a}{d} \\Rightarrow bd = ac $ (lo\u1ea1i) <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span><\/span> ","column":2}]}],"id_ques":286},{"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":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/daiso/bai6/lv2/img\/8.jpg' \/><\/center> T\u1eeb t\u1ec9 l\u1ec7 th\u1ee9c $\\dfrac{a}{b} = \\dfrac{c}{d} (a, b, c, d \\neq 0)$ ta suy ra: ","select":["A. $ \\dfrac{a}{d} = \\dfrac{b}{c} $ ","B. $ \\dfrac{a}{c} = \\dfrac{b}{d} $ ","C. $ \\dfrac{d}{c} = \\dfrac{a}{b} $","D. $ \\dfrac{b}{c} = \\dfrac{d}{a} $"],"explain":" Theo t\u00ednh ch\u1ea5t c\u1ee7a t\u1ec9 l\u1ec7 th\u1ee9c ta c\u00f3: <br\/> $\\dfrac{a}{b} = \\dfrac{c}{d} \\Rightarrow \\dfrac{a}{c} = \\dfrac{b}{d} \\Rightarrow \\dfrac{d}{b} = \\dfrac{c}{a} \\Rightarrow \\dfrac{d}{c} = \\dfrac{b}{a}$ <br\/> $\\Leftrightarrow \\dfrac{a}{b} = \\dfrac{c}{d} \\Rightarrow \\dfrac{a}{c} = \\dfrac{b}{d} $ <br\/> <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span><\/span> ","column":2}]}],"id_ques":287},{"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":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/daiso/bai6/lv2/img\/8.jpg' \/><\/center> $6,51 : 15,19 $ v\u00e0 $0,1 : 0,02 $ l\u1eadp th\u00e0nh m\u1ed9t t\u1ec9 l\u1ec7 th\u1ee9c \u0111\u00fang hay sai? ","select":["A. \u0110\u00fang ","B. Sai "],"hint":" T\u00ednh t\u1eebng t\u1ec9 s\u1ed1 r\u1ed3i so s\u00e1nh.","explain":" Ta c\u00f3: $ 6,51 : 15,19 = \\dfrac{651}{100} : \\dfrac{1519}{100} = \\dfrac{651}{1519}= \\dfrac{3}{7} $ <br\/> $0,1 : 0,02 = \\dfrac{1}{10} : \\dfrac{2}{100} = \\dfrac{1}{10} . \\dfrac{100}{2} = 5 $ <br\/> Nh\u1eadn th\u1ea5y $6,51 : 15,19 \\neq 0,1 : 0,02 $ <br\/> N\u00ean hai t\u1ec9 s\u1ed1 n\u00e0y kh\u00f4ng l\u1eadp th\u00e0nh m\u1ed9t t\u1ec9 l\u1ec7 th\u1ee9c <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span><\/span> ","column":2}]}],"id_ques":288},{"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":" $-3\\dfrac{1}{2} : 7$ v\u00e0 $-2\\dfrac{2}{5} : 7\\dfrac{1}{5}$ l\u1eadp th\u00e0nh m\u1ed9t t\u1ec9 l\u1ec7 th\u1ee9c \u0111\u00fang hay sai? ","select":["A. \u0110\u00fang ","B. Sai "],"hint":" T\u00ednh t\u1eebng t\u1ec9 s\u1ed1 r\u1ed3i so s\u00e1nh.","explain":" Ta c\u00f3: $ -3\\dfrac{1}{2} : 7 = \\dfrac{-7}{2} : 7 = \\dfrac{-7}{2} . \\dfrac{1}{7} = \\dfrac{-1}{2} $ <br\/> $ -2\\dfrac{2}{5} : 7\\dfrac{1}{5} = \\dfrac{-12}{5} : \\dfrac{36}{5} = \\dfrac{-12}{5} . \\dfrac{5}{36} = \\dfrac{-12}{36} = \\dfrac{-1}{3} $ <br\/> Nh\u1eadn th\u1ea5y $-3\\dfrac{1}{2} : 7 \\neq -2\\dfrac{2}{5} : 7\\dfrac{1}{5}$ <br\/> N\u00ean hai t\u1ec9 s\u1ed1 n\u00e0y kh\u00f4ng l\u1eadp th\u00e0nh m\u1ed9t t\u1ec9 l\u1ec7 th\u1ee9c <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span><\/span> ","column":2}]}],"id_ques":289},{"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":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/daiso/bai6/lv2/img\/8.jpg' \/><\/center> \u0110\u00e1p \u00e1n n\u00e0o sau \u0111\u00e2y l\u1eadp th\u00e0nh m\u1ed9t t\u1ec9 l\u1ec7 th\u1ee9c? ","select":["A. $\\dfrac{6}{7} : \\dfrac{14}{5}$ v\u00e0 $\\dfrac{7}{3} : \\dfrac{2}{9}$ ","B. $3,5 : 5,25$ v\u00e0 $14 : 21$ "],"hint":" T\u00ednh t\u1eebng t\u1ec9 s\u1ed1 r\u1ed3i so s\u00e1nh.","explain":" <span class='basic_left'> Ta c\u00f3: $A. \\dfrac{6}{7} : \\dfrac{14}{5} = \\dfrac{6}{7}.\\dfrac{5}{14} = \\dfrac{15}{49}$ v\u00e0 $ \\quad \\dfrac{7}{3} : \\dfrac{2}{9} = \\dfrac{7}{3}.\\dfrac{9}{2} = \\dfrac{21}{2} $ <br\/> Nh\u1eadn th\u1ea5y: $\\dfrac{15}{49} \\neq \\dfrac{21}{2} $ <br\/> N\u00ean $\\dfrac{6}{7} : \\dfrac{14}{5}$ v\u00e0 $\\dfrac{7}{3} : \\dfrac{2}{9}$ kh\u00f4ng l\u1eadp th\u00e0nh t\u1ec9 l\u1ec7 th\u1ee9c. <br\/> $ B.3,5 : 5,25 = \\dfrac{35}{10} : \\dfrac{525}{100} = \\dfrac{35}{10}.\\dfrac{100}{525} = \\dfrac{2}{3}$ v\u00e0 $ \\quad 14 : 21 = \\dfrac{2}{3}$ <br\/> Nh\u1eadn th\u1ea5y $3,5 : 5,25$ v\u00e0 $14 : 21$ b\u1eb1ng nhau <br\/> N\u00ean ch\u00fang l\u1eadp th\u00e0nh t\u1ec9 l\u1ec7 th\u1ee9c $3,5 : 5,25 = 14 : 21$ <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span><\/span> ","column":2}]}],"id_ques":290}],"lesson":{"save":0,"level":2}}