{"segment":[{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":10,"ques":" T\u00ecm s\u1ed1 nguy\u00ean x, bi\u1ebft:<br\/>|7 - x| + (-31) = -19","select":["A. x = 5","B. x = 12","C. x = -5 ho\u1eb7c x = 19","D. x = -5 ho\u1eb7c x = 12"],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> Kho\u1ea3ng c\u00e1ch t\u1eeb \u0111i\u1ec3m a \u0111\u1ebfn \u0111i\u1ec3m 0 tr\u00ean tr\u1ee5c s\u1ed1 l\u00e0 gi\u00e1 tr\u1ecb tuy\u1ec7t \u0111\u1ed1i c\u1ee7a s\u1ed1 nguy\u00ean a<br\/>N\u00ean:<b> |x| = a (a $\\in$ N) th\u00ec x = a ho\u1eb7c x = -a<\/b><\/span> <br\/><br\/><span class='basic_left'><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> $\\begin{align*}|7 - x| + (-31) &= -19\\\\|7 - x|&= -19 - (-31) \\\\|7 - x|&= -19 + 31\\\\|7 - x|&= 31 - 19\\\\|7 - x|&= 12\\end{align*}$<br\/>$\\Rightarrow$ 7 - x = 12 ho\u1eb7c 7 - x = -12<br\/>+) <br\/>$\\begin{align*}7 - x &= 12\\\\x&= 7 - 12\\\\x&= - (12 - 7)\\\\x&= -5\\end{align*}$<br\/>+) <br\/>$\\begin{align*}7 - x &= -12\\\\x&= 7 - (-12) \\\\x&= 7 + 12\\\\x&= 19\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> C. x = -5 ho\u1eb7c x = 19<\/span><\/span> <br\/><\/span><\/span>","column":2}]}],"id_ques":1221},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":10,"ques":" T\u00ecm s\u1ed1 nguy\u00ean x, bi\u1ebft:<br\/>|205 - x| - |-40| = |-200|","select":["A. x = 35","B. x = -445","C. x = 35 ho\u1eb7c x = -445","D. x = -35 ho\u1eb7c x = 445"],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> Kho\u1ea3ng c\u00e1ch t\u1eeb \u0111i\u1ec3m a \u0111\u1ebfn \u0111i\u1ec3m 0 tr\u00ean tr\u1ee5c s\u1ed1 l\u00e0 gi\u00e1 tr\u1ecb tuy\u1ec7t \u0111\u1ed1i c\u1ee7a s\u1ed1 nguy\u00ean a<br\/>N\u00ean:<b> |x| = a (a $\\in$ N) th\u00ec x = a ho\u1eb7c x = -a<\/b><\/span> <br\/><br\/><span class='basic_left'><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> $\\begin{align*}|205 - x| - |-40| &= |-200|\\\\|205 - x| - 40&=200 \\\\|205 - x|&= 200 + 40\\\\|205 - x|&= 240\\end{align*}$<br\/>$\\Rightarrow$ 205 - x = 240 ho\u1eb7c 205 - x = -240<br\/>+) <br\/>$\\begin{align*}205 - x &= 240\\\\x&= 205 - 240\\\\x&= - (240 - 205)\\\\x&= -35\\end{align*}$<br\/>+) <br\/>$\\begin{align*}205 - x &= -240\\\\x&= 205 - (-240) \\\\x&= 205 + 240\\\\x&= 445\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> D. x = -35 ho\u1eb7c x = 445<\/span><\/span> <br\/><\/span><\/span>","column":2}]}],"id_ques":1222},{"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":[[["0"],["0"]]],"list":[{"point":10,"width":60,"type_input":"","ques":"T\u00ecm s\u1ed1 nguy\u00ean a, b bi\u1ebft: |a| + |b| = 0<br\/>a = _input_, b = _input_","hint":"","explain":"<span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> Ta c\u00f3:<br\/> |a| $\\ge $ 0 v\u1edbi m\u1ecdi a <br\/> |b| $\\ge $ 0 v\u1edbi m\u1ecdi b <br\/>M\u00e0 |a| + |b| = 0<br\/>$\\Rightarrow$ |a| = 0 ho\u1eb7c |b| = 0<br\/>$\\Rightarrow$ a = 0 ho\u1eb7c b = 0<br\/>V\u1eady c\u00e1c s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u1ea7n l\u01b0\u1ee3t t\u1eeb tr\u00e1i qua ph\u1ea3i l\u00e0: <span class='basic_pink'> 0; 0<\/span><br\/><\/span> <br\/><\/span>"}]}],"id_ques":1223},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":10,"ques":"T\u00ednh gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c<br\/>A = -3192 - x - (-184) + (y + z) t\u1ea1i x = -1247; y = -859; z = 3107","select":["A = -487","A = 487","A = 5727","A = -5727 "],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u01b0\u1edbc 1: Thay gi\u00e1 tr\u1ecb c\u1ee7a x, y v\u00e0 z v\u00e0o bi\u1ec3u th\u1ee9c A<br\/>B\u01b0\u1edbc 2: T\u00ednh gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c<\/span><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> Thay x = -1247; y = -859; z = 3107 v\u00e0o bi\u1ec3u th\u1ee9c A ta \u0111\u01b0\u1ee3c:<br\/>$\\begin{align*}&-3192 - (-1247) - (-184) + (-859 + 3107)\\\\&= -3192 + 1247 + 184 - 859 + 3107\\\\&= -(3192 + 859) + (1247 + 184 + 3107) \\\\ &= -4051 + (1431 + 3107)\\\\&= -4051 + 4538\\\\& =4538 - 4051\\\\&= 487\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> A = 487<\/span><\/span> <br\/>","column":2}]}],"id_ques":1224},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":10,"ques":"T\u00ednh t\u1ed5ng:<br\/>S = 1 - 6 + 11 - 16 + ... - 96 + 101","select":["S = 51","S = 61","S = 41","S = -51 "],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> $\\begin{align*}S &= 1 - 6 + 11 - 16 + ... - 96 + 101\\\\&= (101 - 96) + (91 - 86) + ... + (11 - 6) + 1\\\\&= 5 + 5 + ... + 5 + 1 \\\\ &= 5 . 10 + 1\\\\&= 50 + 1\\\\& =51\\end{align*}$ <br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'>S = 51<\/span><\/span> <br\/><\/span><br\/><span class='basic_left'><b>L\u01b0u \u00fd: <\/b><br\/>T\u1ed5ng tr\u00ean c\u00f3 s\u1ed1 s\u1ed1 h\u1ea1ng l\u00e0: (101 - 1) : 5 + 1 = 21 s\u1ed1 h\u1ea1ng<br\/>$\\Rightarrow$ \u1edf b\u01b0\u1edbc 3 c\u00f3 10 s\u1ed1 5.<\/span>","column":2}]}],"id_ques":1225},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":10,"ques":"R\u00fat g\u1ecdn bi\u1ec3u th\u1ee9c:<br\/> M = x - 20 - [-a + (a - x)] - (a + x)","select":["M = a - 20","M = x - 20","M = x + a - 20","M = x - a - 20 "],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>B\u01b0\u1edbc 1: B\u1ecf ngo\u1eb7c<br\/>B\u01b0\u1edbc 2: Thu g\u1ecdn bi\u1ec3u th\u1ee9c<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> $\\begin{align*}M &= x - 20 - [-a + (a - x)] - (a + x)\\\\&= x - 20 - (-a + a - x) - a - x\\\\&= x - 20 + a - a + x - a - x \\\\ &= x - a - 20 + (a - a) + (x - x)\\\\&= x - a - 20 + 0 + 0\\\\& =x - a - 20\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'>M = x - a - 20<\/span> <\/span> <br\/>","column":2}]}],"id_ques":1226},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":10,"ques":"T\u00ednh gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c:<br\/> M = x - 20 - [-a + (a - x)] - (a + x) t\u1ea1i x = -5; a = -9","select":["M = 16","M = -16","M = 34","M = -34 "],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>B\u01b0\u1edbc 1: Thu g\u1ecdn bi\u1ec3u th\u1ee9c<br\/>B\u01b0\u1edbc 2: Thay gi\u00e1 tr\u1ecb c\u1ee7a x, a v\u00e0o bi\u1ec3u th\u1ee9c v\u1eeba thu g\u1ecdn \u1edf b\u01b0\u1edbc 1<br\/>B\u01b0\u1edbc 3: T\u00ednh gi\u00e1 tr\u1ecb bi\u1ec3u th\u1ee9c<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> $\\begin{align*}M &= x - 20 - [-a + (a - x)] - (a + x)\\\\&= x - 20 - (-a + a - x) - a - x\\\\&= x - 20 + a - a + x - a - x \\\\ &= x - a - 20 + (a - a) + (x - x)\\\\&= x - a - 20 + 0 + 0\\\\& =x - a - 20\\end{align*}$<br\/> Thay x = -5; a = -9 v\u00e0o bi\u1ec3u th\u1ee9c M v\u1eeba thu g\u1ecdn ta \u0111\u01b0\u1ee3c:<br\/>$\\begin{align*}M &= -5 - (-9) - 20\\\\&= -5 + 9 - 20\\\\&= -(5 + 20) + 9 \\\\ &= -25 + 9\\\\&= -16\\end{align*}$ <br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'>M = -16<\/span> <\/span> <br\/>","column":2}]}],"id_ques":1227},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":10,"ques":"Cho bi\u1ec3u th\u1ee9c M = x - (-a) + 8. T\u00ecm x \u0111\u1ec3 M = 18 - (-a - 5)","select":["A. x = 15","B. x = 31"," C. x = 2a + 15","D. x = 2a - 31 "],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>B\u01b0\u1edbc 1: Thay M = 18 - (-a - 5) v\u00e0o bi\u1ec3u th\u1ee9c \u0111\u00e3 cho<br\/>B\u01b0\u1edbc 2: T\u00ecm x<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> M = 18 - (-a - 5) n\u00ean<br\/> $\\begin{align*} 18 - (-a - 5) &= x - (-a) + 8\\\\18 + a + 5&= x + a + 8\\\\a + (18 + 5)&= x + a + 8 \\\\ a + 23&= x + a + 8 \\\\x&= a + 23 - a - 8 \\\\x& =(a - a) + (23 - 8)\\\\x&= 0 + 15\\\\x&= 15\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> A. x = 15<\/span> <\/span> <br\/>","column":2}]}],"id_ques":1228},{"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":[[["20"],["+20"]]],"list":[{"point":10,"width":60,"type_input":"","ques":"Cho $a_0 + a_1 + a_2 + a_3 + a_4 + a_5 + a_6 + a_7 + a_8 + a_9$ = 8. <br\/>Bi\u1ebft $a_1 + a_2 + a_3$ = $a_4 + a_5 + a_6$= $a_7 + a_8 + a_9$ = -4. V\u1eady $a_0$ = _input_ ","hint":"","explain":"<span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> $a_0 + a_1 + a_2 + a_3 + a_4 + a_5 + a_6 + a_7 + a_8 + a_9$ = 8<br\/>$a_0 + (a_1 + a_2 + a_3) + (a_4 + a_5 + a_6) + (a_7 + a_8 + a_9)$ = 8<br\/> $a_0$ + (-4) + (-4) + (-4) = 8<br\/> $a_0$ - (4 + 4 + 4) = 8<br\/> $a_0$ - 12 = 8<br\/> $a_0$ = 8 + 12<br\/>$a_0$ = 20<br\/>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0: <span class='basic_pink'> 20<\/span><\/span> <br\/><\/span>"}]}],"id_ques":1229},{"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"],["2"]]],"list":[{"point":10,"width":60,"type_input":"","ques":"T\u00ecm s\u1ed1 nguy\u00ean a, b bi\u1ebft: |a + 1| + |b - 2| = 0<br\/>a = _input_, b = _input_","hint":"","explain":"<span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> Ta c\u00f3:<br\/> |a + 1| $\\ge $ 0 v\u1edbi m\u1ecdi a <br\/> |b - 2| $\\ge $ 0 v\u1edbi m\u1ecdi b <br\/>M\u00e0 |a + 1| + |b - 2| = 0<br\/>$\\Rightarrow$ |a + 1| = 0 ho\u1eb7c |b - 2| = 0<br\/>$\\Rightarrow$ a + 1 = 0 ho\u1eb7c b - 2 = 0$\\Rightarrow$ a = -1 ho\u1eb7c b = 2<br\/>V\u1eady c\u00e1c s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u1ea7n l\u01b0\u1ee3t t\u1eeb tr\u00e1i qua ph\u1ea3i l\u00e0: <span class='basic_pink'> -1; 2<\/span><br\/><\/span> <br\/><\/span>"}]}],"id_ques":1230}],"lesson":{"save":0,"level":3}}