{"common":{"save":0,"post_id":"980","level":1,"total":20,"point":5,"point_extra":0},"segment":[{"id":"811","post_id":"980","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":"C\u00e1c gi\u00e1 tr\u1ecb t\u01b0\u01a1ng \u1ee9ng c\u1ee7a hai \u0111\u1ea1i l\u01b0\u1ee3ng $x$ v\u00e0 $y$ \u0111\u01b0\u1ee3c cho trong b\u1ea3ng sau: <br\/> <table><tr><td>x<\/td><td>1<\/td><td>3<\/td><td>5<\/td><td>7<\/td><\/tr><tr><td>y<\/td><td>5<\/td><td>15<\/td><td>25<\/td><td>35<\/td><\/tr><\/table> ","select":["A. \u0110\u1ea1i l\u01b0\u1ee3ng $y$ t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi \u0111\u1ea1i l\u01b0\u1ee3ng $x$","B. \u0110\u1ea1i l\u01b0\u1ee3ng $y$ t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi \u0111\u1ea1i l\u01b0\u1ee3ng $x$"],"explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>- N\u1ebfu \u0111\u1ea1i l\u01b0\u1ee3ng $y$ li\u00ean h\u1ec7 v\u1edbi \u0111\u1ea1i l\u01b0\u1ee3ng $x$ theo c\u00f4ng th\u1ee9c $y = kx \\Rightarrow k = \\dfrac{y}{x} $ (v\u1edbi $k$ l\u00e0 h\u1eb1ng s\u1ed1 kh\u00e1c 0) th\u00ec ta n\u00f3i $y$ t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi $x$ theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 $k$. <br\/> - N\u1ebfu \u0111\u1ea1i l\u01b0\u1ee3ng $y$ li\u00ean h\u1ec7 v\u1edbi \u0111\u1ea1i l\u01b0\u1ee3ng $x$ theo c\u00f4ng th\u1ee9c $y = \\dfrac{a}{x} $ hay $xy = a $ (v\u1edbi $a$ l\u00e0 h\u1eb1ng s\u1ed1 kh\u00e1c 0) th\u00ec ta n\u00f3i $y$ t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi $x$ theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 $a$. <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3: $\\dfrac{5}{1} = \\dfrac{15}{3} = \\dfrac{25}{5} = \\dfrac{35}{7} = 5 $ <br\/> Do \u0111\u00f3 \u0111\u1ea1i l\u01b0\u1ee3ng $y$ t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi \u0111\u1ea1i l\u01b0\u1ee3ng $x$. <\/span> <br\/><br\/> <span class='basic_pink'>\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 A. <\/span>","column":1}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:51"},{"id":"812","post_id":"980","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":"Cho bi\u1ebft hai \u0111\u1ea1i l\u01b0\u1ee3ng $x$ v\u00e0 $y$ t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi nhau v\u00e0 khi $x = -2$ th\u00ec $y = 3$ <br\/> H\u1ec7 s\u1ed1 t\u1ec9 k\u1ec7 $k$ c\u1ee7a $y$ \u0111\u1ed1i v\u1edbi $x$ l\u00e0: ","select":["A. $6 $ ","B. $-6 $ ","C. $\\dfrac{-2}{3} $ ","D. $\\dfrac{-3}{2} $ "],"explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>\u00c1p d\u1ee5ng c\u00f4ng th\u1ee9c $y = kx$ \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c t\u01b0\u01a1ng quan t\u1ec9 l\u1ec7 thu\u1eadn gi\u1eefa hai \u0111\u1ea1i l\u01b0\u1ee3ng v\u00e0 x\u00e1c \u0111\u1ecbnh h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7. <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Hai \u0111\u1ea1i l\u01b0\u1ee3ng $x$ v\u00e0 $y$ t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi nhau v\u00e0 khi $x = -2$ th\u00ec $y = 3$ n\u00ean ta c\u00f3: <br\/> $y = kx \\Rightarrow 3 = k.(-2) \\Rightarrow k = \\dfrac{-3}{2} $<\/span> <br\/><br\/> <span class='basic_pink'>\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 D. <\/span>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:51"},{"id":"813","post_id":"980","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":"Hai s\u1ed1 $x$ v\u00e0 $y$ t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi $\\dfrac{3}{4} $ v\u00e0 $\\dfrac{4}{3} .$ T\u00ednh $x$ v\u00e0 $y$ bi\u1ebft $x + y = -50 $ ","select":["A. $x = 18, y = 32 $ ","B. $x = -32, y = -18 $ ","C. $x = -18, y = -32 $ ","D. $x = -32, y = 18 $ "],"explain":" $x$ v\u00e0 $y$ t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi $\\dfrac{3}{4} $ v\u00e0 $\\dfrac{4}{3} $ n\u00ean ta c\u00f3: <br\/> $\\begin{aligned}&\\dfrac{x}{\\dfrac{3}{4}}=\\dfrac{y}{\\dfrac{4}{3}}=\\dfrac{x+y}{\\dfrac{3}{4}+\\dfrac{4}{3}} =\\dfrac{-50}{\\dfrac{25}{12}}=-24 \\\\ & \\Rightarrow \\left\\{\\begin{aligned} & x=\\dfrac{3}{4}.(-24)=-18 \\\\ & y=\\dfrac{4}{3}.(-24)=-32 \\\\ \\end{aligned} \\right. \\\\ \\end{aligned}$ <br\/><br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C. <\/span><br\/>","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:51"}]}