{"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":"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}]}],"id_ques":811},{"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}]}],"id_ques":812},{"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}]}],"id_ques":813},{"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 ngh\u1ecbch v\u1edbi nhau v\u00e0 khi $x = -12$ th\u00ec $y = 4$ <br\/> Bi\u1ec3u di\u1ec5n $y$ theo $x$ nh\u01b0 sau: ","select":["A. $y = -3x $ ","B. $ y = -48x $ ","C. $y = \\dfrac{-1}{3}x $ ","D. $y = \\dfrac{-48}{x} $ "],"explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>\u00c1p d\u1ee5ng c\u00f4ng th\u1ee9c $y = \\dfrac{a}{x} $ \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c t\u01b0\u01a1ng quan t\u1ec9 l\u1ec7 ngh\u1ecbch gi\u1eefa hai \u0111\u1ea1i l\u01b0\u1ee3ng. <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> Hai \u0111\u1ea1i l\u01b0\u1ee3ng $x$ v\u00e0 $y$ t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi nhau n\u00ean $x.y = a $ <br\/> Khi $x = -12$ th\u00ec $y = 4$ n\u00ean $a = (-12).4 = -48 $ <br\/> $y = \\dfrac{a}{x} $ m\u00e0 $a = -48$ n\u00ean $y = \\dfrac{-48}{x} $<\/span> <br\/><br\/> <span class='basic_pink'>\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 D. <\/span>","column":2}]}],"id_ques":814},{"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":"N\u1ebfu $y$ t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi $x$ v\u00e0 $y = 10$ th\u00ec $x = 7.$ Khi $x = 5$ th\u00ec $ y $ b\u1eb1ng: ","select":["A. $10 $ ","B. $12 $ ","C. $14 $ ","D. $16 $ "],"explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>\u00c1p d\u1ee5ng c\u00f4ng th\u1ee9c $y = \\dfrac{a}{x} $ \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c t\u01b0\u01a1ng quan t\u1ec9 l\u1ec7 ngh\u1ecbch gi\u1eefa hai \u0111\u1ea1i l\u01b0\u1ee3ng. <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> Hai \u0111\u1ea1i l\u01b0\u1ee3ng $x$ v\u00e0 $y$ t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi nhau n\u00ean $x.y = a $ <br\/> Khi $x = 7$ th\u00ec $y = 10$ n\u00ean $a = 7.10 = 70 $ <br\/> $y = \\dfrac{a}{x} $ m\u00e0 $a = 70$ n\u00ean $y = \\dfrac{70}{x} $ <br\/> Khi $x = 5$ th\u00ec $y = \\dfrac{70}{5} = 14 $<\/span> <br\/><br\/> <span class='basic_pink'>\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C. <\/span>","column":4}]}],"id_ques":815},{"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":"Cho hai \u0111\u1ea1i l\u01b0\u1ee3ng $x$ v\u00e0 $y$: <br\/> <table><tr><td>$x$<\/td><td>$x_{1}$<\/td><td>$x_{2}$<\/td><\/tr><tr><td>$y$<\/td><td>$y_{1}$<\/td><td>$y_{2}$<\/td><\/tr><\/table> <br\/> N\u1ebfu hai \u0111\u01b0\u1ee3ng n\u00e0y t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi nhau th\u00ec: ","select":["A. $\\dfrac{x_{1}}{x_{2}} = \\dfrac{y_{2}}{y_{1}} $ ","B. $\\dfrac{x_{1}}{x_{2}} = \\dfrac{y_{1}}{y_{2}} $ ","C. $\\dfrac{x_{1}}{y_{1}} = \\dfrac{x_{2}}{y_{2}} $ ","D. $x_{1}.y_{2} = x_{2}.y_{1} $ "],"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 = \\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\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> Hai \u0111\u1ea1i l\u01b0\u1ee3ng $x$ v\u00e0 $y$ t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi nhau n\u00ean ta c\u00f3: <br\/> $\\dfrac{x_{1}}{x_{2}} = \\dfrac{y_{2}}{y_{1}} $ hay $x_{1}.y_{1} = x_{2}.y_{2} $ <\/span> <br\/><br\/> <span class='basic_pink'>\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 A. <\/span>","column":2}]}],"id_ques":816},{"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":"M\u1ed9t t\u1ea5n n\u01b0\u1edbc bi\u1ec3n ch\u1ee9a 25kg mu\u1ed1i. H\u1ecfi 250g n\u01b0\u1edbc bi\u1ec3n \u0111\u00f3 ch\u1ee9a bao nhi\u00eau gam mu\u1ed1i? ","select":["A. 0,625(g) ","B. 6,25(g) ","C. 62,5(g) ","D. 0,0625(g) "],"explain":"<span class='basic_left'> \u0110\u1ed5i: 1 t\u1ea5n = 1 000 000 (gam); 25kg = 25 000 (gam) <br\/> T\u00f3m t\u1eaft \u0111\u1ec1 b\u00e0i: <br\/> <table><tr><th>Kh\u1ed1i l\u01b0\u1ee3ng n\u01b0\u1edbc bi\u1ec3n<\/th><th>Kh\u1ed1i l\u01b0\u1ee3ng mu\u1ed1i<\/th><\/tr><tr><td>1000000 gam<\/td><td>25000 gam<\/td><\/tr><tr><td>250 gam<\/td><td>x gam?<\/td><\/tr><\/table><br\/> G\u1ecdi l\u01b0\u1ee3ng mu\u1ed1i c\u00f3 trong 250g n\u01b0\u1edbc bi\u1ec3n l\u00e0 $x (x >0) $ (g) <br\/> V\u00ec l\u01b0\u1ee3ng n\u01b0\u1edbc bi\u1ec3n v\u00e0 l\u01b0\u1ee3ng mu\u1ed1i ch\u1ee9a trong \u0111\u00f3 l\u00e0 hai \u0111\u1ea1i l\u01b0\u1ee3ng t\u1ec9 l\u1ec7 thu\u1eadn <br\/> N\u00ean theo t\u00ednh ch\u1ea5t c\u1ee7a \u0111\u1ea1i l\u01b0\u1ee3ng t\u1ec9 l\u1ec7 thu\u1eadn ta c\u00f3: <br\/> $\\dfrac{25000}{1000000} = \\dfrac{x}{250} \\Rightarrow x = \\dfrac{25000.250}{1000000} = 6,25 (g) $ <br\/><br\/> <span class='basic_pink'>\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span>","column":4}]}],"id_ques":817},{"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":"M\u1ed9t h\u00ecnh ch\u1eef nh\u1eadt c\u00f3 chu vi l\u00e0 64cm. Bi\u1ebft chi\u1ec1u d\u00e0i v\u00e0 chi\u1ec1u r\u1ed9ng c\u1ee7a h\u00ecnh ch\u1eef nh\u1eadt t\u1ec9 l\u1ec7 v\u1edbi 5 v\u00e0 3. Khi \u0111\u00f3 chi\u1ec1u d\u00e0i v\u00e0 chi\u1ec1u r\u1ed9ng l\u1ea7n l\u01b0\u1ee3t l\u00e0: ","select":["A. 40cm, 24cm","B. 20cm, 12cm ","C. 10cm, 6cm","D. 20cm, 30cm "],"explain":"<span class='basic_left'>G\u1ecdi chi\u1ec1u d\u00e0i v\u00e0 chi\u1ec1u r\u1ed9ng c\u1ee7a h\u00ecnh ch\u1eef nh\u1eadt l\u1ea7n l\u01b0\u1ee3t l\u00e0 x, y (x, y > 0) <br\/> Theo \u0111\u1ec1 b\u00e0i ta c\u00f3: $\\dfrac{x}{5} = \\dfrac{y}{3} $ v\u00e0 $x + y = \\dfrac{64}{2} = 32 $ <br\/> \u00c1p d\u1ee5ng t\u00ednh ch\u1ea5t d\u00e3y t\u1ec9 s\u1ed1 b\u1eb1ng nhau, ta \u0111\u01b0\u1ee3c: <br\/> $\\begin{aligned}& \\dfrac{x}{5}=\\dfrac{y}{3}=\\dfrac{x+y}{5+3}=\\dfrac{32}{8}=4 \\\\ & \\Rightarrow \\left\\{ \\begin{aligned} & x=5.4=20 \\\\ & y=3.4=12 \\\\ \\end{aligned} \\right. \\\\ \\end{aligned}$ <br\/> V\u1eady chi\u1ec1u d\u00e0i v\u00e0 chi\u1ec1u r\u1ed9ng c\u1ee7a h\u00ecnh ch\u1eef nh\u1eadt l\u1ea7n l\u01b0\u1ee3t l\u00e0: 20(cm), 12(cm) <br\/><br\/> <span class='basic_pink'>\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span>","column":4}]}],"id_ques":818},{"time":24,"part":[{"title":"\u0110i\u1ec1n t\u1eeb th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank_random","correct":[[["240"],["160"],["120"]]],"list":[{"point":5,"width":40,"content":"","type_input":"","ques":"Chia s\u1ed1 520 th\u00e0nh ba ph\u1ea7n t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi 2; 3; 4? <br\/>T\u00ecm ba ph\u1ea7n \u0111\u00f3.<br\/> <b> \u0110\u00e1p s\u1ed1: <\/b> _input_; _input_; _input_","explain":"<span class='basic_left'>G\u1ecdi ba ph\u1ea7n c\u1ea7n t\u00ecm l\u00e0 x, y, z. <br\/> V\u00ec x, y, z t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi 2; 3; 4 n\u00ean ta c\u00f3: 2x = 3y = 4z <br\/> Do \u0111\u00f3: $\\begin{aligned} &\\dfrac{x}{\\dfrac{1}{2}}=\\dfrac{y}{\\dfrac{1}{3}}=\\dfrac{z}{\\dfrac{1}{4}}=\\dfrac{x+y+z}{\\dfrac{1}{2}+\\dfrac{1}{3}+\\dfrac{1}{4}}= \\dfrac{520}{\\dfrac{13}{12}}=480 \\\\ & \\\\ \\end{aligned}$ <br\/> Suy ra $ x=\\dfrac{1}{2}.480=240 \\\\ y=\\dfrac{1}{3}.480=160 \\\\ z=\\dfrac{1}{4}.480=120 $ <br\/> <br\/> <span class='basic_pink'> V\u1eady c\u00e1c s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u1ea7n l\u01b0\u1ee3t l\u00e0 $ 240; 160; 120$ <\/span>"}]}],"id_ques":819},{"time":24,"part":[{"title":"\u0110i\u1ec1n t\u1eeb th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["-4"],["-12"]]],"list":[{"point":5,"width":50,"content":"","type_input":"","ques":"Cho bi\u1ebft hai \u0111\u1ea1i l\u01b0\u1ee3ng $x$ v\u00e0 $y$ t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi nhau. <br\/> H\u00e3y \u0111i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng trong b\u1ea3ng sau. <br\/> <table><tr><td>x<\/td><td>8<\/td><td>6<\/td><td>_input_<\/td><\/tr><tr><td>y<\/td><td>-9<\/td><td>_input_<\/td><td>18<\/td><\/tr><\/table> ","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>\u00c1p d\u1ee5ng c\u00f4ng th\u1ee9c $y = \\dfrac{a}{x} $ \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c t\u01b0\u01a1ng quan t\u1ec9 l\u1ec7 ngh\u1ecbch gi\u1eefa hai \u0111\u1ea1i l\u01b0\u1ee3ng. <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> Hai \u0111\u1ea1i l\u01b0\u1ee3ng $x$ v\u00e0 $y$ t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi nhau n\u00ean $x.y = a $ <br\/> Khi $x = 8 $ th\u00ec $y = -9$ n\u00ean $a = 8.(-9) = -72 $ <br\/> $y = \\dfrac{a}{x} $ m\u00e0 $a = -72$ n\u00ean $y = \\dfrac{-72}{x} $ <br\/> Khi $x = 6$ th\u00ec $y = \\dfrac{-72}{6} = -12 $ <br\/> Khi $y = 18 $ th\u00ec $x = \\dfrac{-72}{18} = -4 $ <br\/> <span class='basic_pink'> V\u1eady c\u00e1c s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u1ea7n l\u01b0\u1ee3t l\u00e0 $-4; - 12$ <\/span><\/span>"}]}],"id_ques":820},{"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":"Cho h\u00e0m s\u1ed1 $y = f(x) = \\dfrac{1}{3}x^{2} -1 $. Khi \u0111\u00f3: ","select":["A. $f(1) = 1 $","B. $f(3) = -1 $","C. $f(-1) = \\dfrac{-2}{3} $ ","D. $ f(0) = \\dfrac{-2}{3} $ "],"explain":" Ta c\u00f3: $y = f(x) = \\dfrac{1}{3}x^{2} -1 $ <br\/> Do \u0111\u00f3: $f(0) = \\dfrac{1}{3}.0^{2} - 1 = -1 \\Rightarrow D. Sai \\\\ f(3) = \\dfrac{1}{3}.3^{2} - 1 = 2 \\Rightarrow B. Sai \\\\ f(-1) = \\dfrac{1}{3}(-1)^{2} - 1 = \\dfrac{-2}{3} \\Rightarrow C. \u0110\u00fang \\\\ f(1) = \\dfrac{1}{3}.1^{2} - 1 = \\dfrac{-2}{3} \\Rightarrow A. Sai $<br\/><br\/> <span class='basic_pink'>\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C. <\/span>","column":2}]}],"id_ques":821},{"time":24,"part":[{"title":"\u0110i\u1ec1n t\u1eeb th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["1"]]],"list":[{"point":5,"width":20,"content":"","type_input":"","ques":"Cho h\u00e0m s\u1ed1 $y = ax^{3} (a \\neq 0) .$ Cho $f(2) = 8 $ th\u00ec $a = \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}$","explain":"Ta c\u00f3: $f(2) = 8 \\\\ \\Leftrightarrow 8 = a.2^{3} \\\\ \\Leftrightarrow 8 = a.8 \\\\ \\Rightarrow a = 1 $ <br\/><br\/> <span class='basic_pink'>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u00e0 $ 1$ <\/span>"}]}],"id_ques":822},{"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":"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>$-3$<\/td><td>$-2$<\/td><td>$-1$<\/td><td>0<\/td><td>$-2$<\/td><td>$-5$<\/td><\/tr><tr><td>y<\/td><td>1<\/td><td>2<\/td><td>3<\/td><td>4<\/td><td>0<\/td><td>5<\/td><\/tr><\/table> <br\/> \u0110\u1ea1i l\u01b0\u1ee3ng y c\u00f3 ph\u1ea3i l\u00e0 h\u00e0m s\u1ed1 c\u1ee7a \u0111\u1ea1i l\u01b0\u1ee3ng x kh\u00f4ng? ","select":["C\u00f3","Kh\u00f4ng"],"explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>C\u1ea7n ki\u1ec3m tra \u0111i\u1ec1u ki\u1ec7n: m\u1ed7i gi\u00e1 tr\u1ecb c\u1ee7a \u0111\u1ea1i l\u01b0\u1ee3ng x \u0111\u01b0\u1ee3c t\u01b0\u01a1ng \u1ee9ng v\u1edbi m\u1ed9t v\u00e0 ch\u1ec9 m\u1ed9t gi\u00e1 tr\u1ecb c\u1ee7a \u0111\u1ea1i l\u01b0\u1ee3ng y. <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta th\u1ea5y gi\u00e1 tr\u1ecb $x = -2$ c\u1ee7a \u0111\u1ea1i l\u01b0\u1ee3ng x \u0111\u01b0\u1ee3c t\u01b0\u01a1ng \u1ee9ng v\u1edbi hai gi\u00e1 tr\u1ecb kh\u00e1c nhau c\u1ee7a \u0111\u1ea1i l\u01b0\u1ee3ng y l\u00e0 2 v\u00e0 0 <br\/> N\u00ean \u0111\u1ea1i l\u01b0\u1ee3ng y kh\u00f4ng ph\u1ea3i l\u00e0 h\u00e0m s\u1ed1 c\u1ee7a \u0111\u1ea1i l\u01b0\u1ee3ng x. <\/span> <br\/><br\/> <span class='basic_pink'>\u0110\u00e1p \u00e1n l\u00e0 ''Kh\u00f4ng''. <\/span>","column":2}]}],"id_ques":823},{"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":"X\u00e1c \u0111\u1ecbnh t\u1ecda \u0111\u1ed9 c\u1ee7a c\u00e1c \u0111i\u1ec3m E, M, Q trong h\u00ecnh. <br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/daiso/bai18/lv1/img\/D7B18-01.png' \/><\/center>","select":["A. $E(1; -3), M(0; 2), Q(0; -1)$ ","B. $E(-3; 1), M(0; 2), Q(-1; 0)$ ","C. $E(-3; 1), M(2; 0), Q(0; -1)$ ","D. $E(-3; 1), M(2; 0), Q(-1; 0)$ "],"explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span> <br\/> Mu\u1ed1n t\u00ecm t\u1ecda \u0111\u1ed9 c\u1ee7a \u0111i\u1ec3m cho tr\u01b0\u1edbc: <br\/> - T\u1eeb \u0111i\u1ec3m \u0111\u00e3 cho k\u1ebb \u0111\u01b0\u1eddng th\u1eb3ng vu\u00f4ng g\u00f3c v\u1edbi tr\u1ee5c ho\u00e0nh, c\u1eaft tr\u1ee5c ho\u00e0nh t\u1ea1i m\u1ed9t \u0111i\u1ec3m bi\u1ec3u di\u1ec5n ho\u00e0nh \u0111\u1ed9 c\u1ee7a \u0111i\u1ec3m \u0111\u00f3. <br\/> - T\u1eeb \u0111i\u1ec3m \u0111\u00e3 cho k\u1ebb \u0111\u01b0\u1eddng th\u1eb3ng vu\u00f4ng g\u00f3c v\u1edbi tr\u1ee5c tung, c\u1eaft tr\u1ee5c tung t\u1ea1i m\u1ed9t \u0111i\u1ec3m bi\u1ec3u di\u1ec5n tung \u0111\u1ed9 c\u1ee7a \u0111i\u1ec3m \u0111\u00f3. <br\/> - Ho\u00e0nh \u0111\u1ed9 v\u00e0 tung \u0111\u1ed9 t\u00ecm \u0111\u01b0\u1ee3c l\u00e0 t\u1ecda \u0111\u1ed9 c\u1ee7a \u0111i\u1ec3m \u0111\u00e3 cho. <\/span> <br\/> <br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>T\u1ecda \u0111\u1ed9 \u0111i\u1ec3m $E$ l\u00e0 $E(-3; 1)$ <br\/> T\u1ecda \u0111\u1ed9 \u0111i\u1ec3m $M$ l\u00e0 $M(2; 0)$ <br\/> T\u1ecda \u0111\u1ed9 \u0111i\u1ec3m $Q$ l\u00e0 $Q(0; -1)$ <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C. <\/span> <\/span>","column":2}]}],"id_ques":824},{"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":"\u0110i\u1ec3m $E(a; -0,2)$ thu\u1ed9c \u0111\u1ed3 th\u1ecb h\u00e0m s\u1ed1 $y = 4x.$ T\u00ecm h\u1ec7 s\u1ed1 a ","select":["A. $a = -0,5$ ","B. $a = -0,05$ ","C. $a = 0,05 $","D. $a = -1 $"],"explain":"Thay $x = a, y = -0,2$ v\u00e0o h\u00e0m s\u1ed1 $y = 4x$ ta \u0111\u01b0\u1ee3c: <br\/> $-0,2 = 4.a \\Rightarrow a = \\dfrac{-0,2}{4} = -0,05 $ <br\/> <br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span> <\/span>","column":2}]}],"id_ques":825},{"time":24,"part":[{"title":"\u0110i\u1ec1n t\u1eeb th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["0"],["5"]]],"list":[{"point":5,"width":20,"content":"","type_input":"","ques":"T\u00ecm \u0111i\u1ec3m A tr\u00ean tr\u1ee5c tung m\u00e0 thu\u1ed9c \u0111\u1ed3 th\u1ecb c\u1ee7a h\u00e0m s\u1ed1 $y = \\dfrac{1}{2}x + 5 $ <br\/> <b> \u0110\u00e1p s\u1ed1: <\/b> $A(\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}; \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{})$","explain":"\u0110i\u1ec3m A n\u1eb1m tr\u00ean tr\u1ee5c tung n\u00ean t\u1ecda \u0111\u1ed9 \u0111i\u1ec3m A c\u00f3 d\u1ea1ng $A(0; y_{A}) $ <br\/> Thay $x = 0; y = y_{A} $ v\u00e0o h\u00e0m s\u1ed1 $y = \\dfrac{1}{2}x + 5 $ ta \u0111\u01b0\u1ee3c: <br\/> $y_{A} = \\dfrac{1}{2}.0 + 5 = 5 $ <br\/> Suy ra t\u1ecda \u0111\u1ed9 \u0111i\u1ec3m A l\u00e0 A(0; 5) <br\/> <span class='basic_pink'>V\u1eady c\u00e1c s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u1ea7n l\u01b0\u1ee3t l\u00e0 $0; 5$<\/span> "}]}],"id_ques":826},{"time":9,"part":[{"title":"V\u1ebd \u0111\u1ed3 th\u1ecb h\u00e0m s\u1ed1.","title_trans":"","temp":"coordinates","correct":[["1,1","-4.5,-4.5","-4,-4","-3.5,-3.5","-3,-3","-2.5,-2.5","-2,-2","-1.5,-1.5","-1,-1","-0.5,-0.5","0.5,0.5","1,1","4.5,4.5","4,4","3.5,3.5","3,3","2.5,2.5","2,2","1.5,1.5"]],"list":[{"point":5,"toa_do":[["0","0",""]],"is_click":1,"name_toado_click":"A","draw_line":1,"ques":"V\u1ebd \u0111\u1ed3 th\u1ecb h\u00e0m s\u1ed1 y = x <br\/> <br\/>_inputduongthang_ <br\/> H\u00e3y click th\u00eam m\u1ed9t \u0111i\u1ec3m thu\u1ed9c \u0111\u1ed3 th\u1ecb \u0111\u1ec3 v\u1ebd \u0111\u1ed3 th\u1ecb h\u00e0m s\u1ed1.","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> V\u1ebd \u0111\u01b0\u1eddng th\u1eb3ng qua \u0111i\u1ec3m O(0; 0) v\u00e0 \u0111i\u1ec3m A(1; a)<\/span> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/daiso/bai18/lv1/img\/D7B18-04.png' \/><\/center> <br\/> \u0110\u1ed3 th\u1ecb h\u00e0m s\u1ed1 y = x l\u00e0 \u0111\u01b0\u1eddng th\u1eb3ng OA v\u1edbi O(0; 0) v\u00e0 A(1; 1) <\/span> <br\/><br\/><br\/>"}]}],"id_ques":827},{"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":" \u0110i\u1ec3m n\u00e0o sau \u0111\u00e2y kh\u00f4ng thu\u1ed9c \u0111\u1ed3 th\u1ecb h\u00e0m s\u1ed1 $y = 2x? $","select":["A. $A(1; 2)$ ","B. $B(-1,5; -3) $ ","C. $C(-1,5; 3) $ ","D. $D\\left(\\dfrac{1}{4}; 0,5 \\right) $ "],"explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>\u0110i\u1ec3m $M(x_{0};y_{0})$ thu\u1ed9c \u0111\u1ed3 th\u1ecb c\u1ee7a h\u00e0m s\u1ed1 $y = f(x) $ n\u1ebfu $y_{0} = f(x_{0}) $ <\/span> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <span class='basic_left'> A. Thay $x = 1 $ v\u00e0o $y = 2x $ ta \u0111\u01b0\u1ee3c $y = 2.1 = 2 $ <br\/> $\\Rightarrow $ \u0111i\u1ec3m $A(1; 2)$ thu\u1ed9c \u0111\u1ed3 th\u1ecb h\u00e0m s\u1ed1 $y = 2x.$ <br\/> B. Thay $x = -1,5 $ v\u00e0o $y = 2x $ ta \u0111\u01b0\u1ee3c $y = 2.(-1,5) = -3 $ <br\/> $\\Rightarrow $ \u0111i\u1ec3m $B(-1,5; -3)$ thu\u1ed9c \u0111\u1ed3 th\u1ecb h\u00e0m s\u1ed1 $y = 5x^{2} - 2 $ <br\/> C. Thay $x = -1,5 $ v\u00e0o $y = 2x $ ta \u0111\u01b0\u1ee3c $y = 2.(-1,5) = -3 \\neq 3 $ <br\/> $\\Rightarrow $ \u0111i\u1ec3m $C(-1,5; 3)$ kh\u00f4ng thu\u1ed9c \u0111\u1ed3 th\u1ecb h\u00e0m s\u1ed1 $y = 2x.$ <\/span> <br\/><br\/> <span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C. <\/span><br\/>","column":2}]}],"id_ques":828},{"time":24,"part":[{"title":"\u0110i\u1ec1n t\u1eeb th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["1"],["2"]]],"list":[{"point":5,"width":20,"content":"","type_input":"","ques":"Vi\u1ebft t\u1ecda \u0111\u1ed9 \u0111i\u1ec3m A trong h\u1ec7 tr\u1ee5c t\u1ecda \u0111\u1ed9 Oxy \u1edf h\u00ecnh sau: <br\/><br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/daiso/bai18/lv1/img\/D7B18-07.png' \/><\/center> <br\/><br\/> \u0110\u00e1p \u00e1n: $A(\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}; \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{})$ ","explain":"\u0110i\u1ec3m A c\u00f3 t\u1ecda \u0111\u1ed9 l\u00e0 A(1; 2) "}]}],"id_ques":829},{"time":24,"part":[{"title":"\u0110i\u1ec1n t\u1eeb th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["-3"],["-9"],["-12"]]],"list":[{"point":5,"width":50,"content":"","type_input":"","ques":"Cho b\u1ea3ng: <br\/> <table><tr><td>x<\/td><td>1<\/td><td>2<\/td><td>3<\/td><td>4<\/td><\/tr><tr><td>y<\/td><td>_input_<\/td><td>-6<\/td><td>_input_<\/td><td>_input_<\/td><\/tr><\/table> <br\/> H\u00e3y \u0111i\u1ec1n c\u00e1c s\u1ed1 v\u00e0o \u00f4 tr\u1ed1ng trong b\u1ea3ng \u0111\u1ec3 \u0111\u01b0\u1ee3c x v\u00e0 y l\u00e0 hai \u0111\u1ea1i l\u01b0\u1ee3ng t\u1ec9 l\u1ec7 thu\u1eadn. ","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 \\Rightarrow k = \\dfrac{y}{x} $ \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. <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <br\/> Hai \u0111\u1ea1i l\u01b0\u1ee3ng $x$ v\u00e0 $y$ t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi nhau n\u00ean $k = \\dfrac{y}{x} $ <br\/> Khi $x = 2 $ th\u00ec $y = 6 $ n\u00ean $k = \\dfrac{-6}{2} = -3 $ <br\/> $y = kx $ m\u00e0 $k = -3$ n\u00ean $y = -3x $ <br\/> \u0110\u00e1p s\u1ed1: <br\/> <table><tr><td>x<\/td><td>1<\/td><td>2<\/td><td>3<\/td><td>4<\/td><\/tr><tr><td>y<\/td><td>$-3$<\/td><td>$-6$<\/td><td>$-9$<\/td><td>$-12$<\/td><\/tr><\/table> <\/span>"}]}],"id_ques":830}],"lesson":{"save":0,"level":1}}