{"segment":[{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u v\u00e0 s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["<"],["6"]]],"list":[{"point":5,"width":50,"content":"","type_input":"","ques":"Gi\u1ea3i b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh: $3x < 18$<br\/><b>\u0110\u00e1p \u00e1n:<\/b> $x$ _input_ _input_","hint":"","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$3x < 18$ <br\/> $\\Leftrightarrow 3x : 3 < 18 : 3$ (Chia c\u1ea3 hai v\u1ebf cho $3$)<br\/>$\\Leftrightarrow x < 6$<br\/>V\u1eady t\u1eadp nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $\\left\\{x \\mid x < 6\\right\\}$<br\/>D\u1ea5u v\u00e0 s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u1ea7n l\u01b0\u1ee3t l\u00e0 <span class='basic_pink'>\"<\"; $6$<\/span><\/span>"}]}],"id_ques":1101},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u v\u00e0 s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["<"],["28"]]],"list":[{"point":5,"width":50,"content":"","type_input":"","ques":"Gi\u1ea3i b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh: $x - 8 < 20$<br\/><b>\u0110\u00e1p \u00e1n:<\/b> $x$ _input_ _input_","hint":"","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$x - 8 < 20$ <br\/> $\\Leftrightarrow x < 20 + 8$ (Chuy\u1ec3n v\u1ebf $-8$ v\u00e0 \u0111\u1ed5i d\u1ea5u th\u00e0nh 8)<br\/>$\\Leftrightarrow x < 28$<br\/>V\u1eady t\u1eadp nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $\\left\\{x \\mid x < 28\\right\\}$<br\/>D\u1ea5u v\u00e0 s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u1ea7n l\u01b0\u1ee3t l\u00e0 <span class='basic_pink'>\"<\"; $28$<\/span><\/span>"}]}],"id_ques":1102},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u v\u00e0 s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[[">"],["18"]]],"list":[{"point":5,"width":50,"content":"","type_input":"","ques":"Gi\u1ea3i b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh: $0,5x > 9$<br\/><b>\u0110\u00e1p \u00e1n:<\/b> $x$ _input_ _input_","hint":"","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$0,5x > 9$ <br\/> $\\Leftrightarrow 0,5x.2 > 9.2$ (Nh\u00e2n c\u1ea3 hai v\u1ebf v\u1edbi $2$)<br\/>$\\Leftrightarrow x > 18$<br\/>V\u1eady t\u1eadp nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $\\left\\{x \\mid x > 18\\right\\}$<br\/>D\u1ea5u v\u00e0 s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u1ea7n l\u01b0\u1ee3t l\u00e0 <span class='basic_pink'>\">\"; $18$<\/span><\/span>"}]}],"id_ques":1103},{"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/lop8/toan/daiso/bai26/lv1/img\/3.jpg' \/><\/center><br\/>Gi\u1ea3i b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $4x - 7 < 5$","select":[" A. $\\left\\{x \\mid x > 3\\right\\}$"," B. $\\left\\{x \\mid x < 3\\right\\}$","C. $\\left\\{x \\mid x > \\dfrac{-1}{2} \\right\\}$","D. $\\left\\{x \\mid x < \\dfrac{-1}{2} \\right\\}$"],"hint":"S\u1eed d\u1ee5ng quy t\u1eafc chuy\u1ec3n v\u1ebf v\u00e0 quy t\u1eafc nh\u00e2n ho\u1eb7c quy t\u1eafc chia v\u1edbi m\u1ed9t s\u1ed1 \u0111\u1ec3 gi\u1ea3i.","explain":"<span class='basic_left'>Ta c\u00f3:<br\/> $4x - 7 < 5$<br\/>$\\Leftrightarrow 4x < 5 + 7$ (Chuy\u1ec3n v\u1ebf $-7$ v\u00e0 \u0111\u1ed5i d\u1ea5u th\u00e0nh $7$)<br\/>$\\Leftrightarrow 4x < 12$<br\/>$\\Leftrightarrow 4x : 4 < 12 : 4$ (Chia hai v\u1ebf cho $4$)<br\/>$\\Leftrightarrow x < 3$<br\/>V\u1eady t\u1eadp nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $\\left\\{x \\mid x < 3\\right\\}$ <br\/>\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>B. $\\left\\{x \\mid x < 3\\right\\}$<\/span><\/span>","column":2}]}],"id_ques":1104},{"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/lop8/toan/daiso/bai26/lv1/img\/5.jpg' \/><\/center><br\/>Gi\u1ea3i b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $5x > 8x - 9$","select":[" A. $\\left\\{x \\mid x > 3\\right\\}$"," B. $\\left\\{x \\mid x < 3\\right\\}$","C. $\\left\\{x \\mid x > \\dfrac{-1}{2} \\right\\}$","D. $\\left\\{x \\mid x < \\dfrac{-1}{2} \\right\\}$"],"hint":"S\u1eed d\u1ee5ng quy t\u1eafc chuy\u1ec3n v\u1ebf v\u00e0 quy t\u1eafc nh\u00e2n ho\u1eb7c quy t\u1eafc chia v\u1edbi m\u1ed9t s\u1ed1 \u0111\u1ec3 gi\u1ea3i.","explain":"<span class='basic_left'>Ta c\u00f3 $5x > 8x - 9$<br\/>$\\Leftrightarrow 5x - 8x > -9$ (Chuy\u1ec3n v\u1ebf $8x$ v\u00e0 \u0111\u1ed5i d\u1ea5u th\u00e0nh $-8x$)<br\/>$\\Leftrightarrow -3x > -9$<br\/>$\\Leftrightarrow -3x : (-3) < (-9) : (-3)$ (Chia hai v\u1ebf cho $-3$)<br\/>$\\Leftrightarrow x < 3$<br\/>V\u1eady t\u1eadp nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $\\left\\{x \\mid x < 3\\right\\}$ <br\/>\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>B. $\\left\\{x \\mid x < 3\\right\\}$<\/span><\/span>","column":2}]}],"id_ques":1105},{"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/lop8/toan/daiso/bai26/lv1/img\/7.jpg' \/><\/center><br\/>Gi\u1ea3i b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $3x + 8 > 2x$","select":[" A. $\\left\\{x \\mid x > -8\\right\\}$"," B. $\\left\\{x \\mid x < -8\\right\\}$","C. $\\left\\{x \\mid x > \\dfrac{-8}{5} \\right\\}$","D. $\\left\\{x \\mid x < \\dfrac{-8}{5} \\right\\}$"],"hint":"S\u1eed d\u1ee5ng quy t\u1eafc chuy\u1ec3n v\u1ebf v\u00e0 quy t\u1eafc nh\u00e2n ho\u1eb7c quy t\u1eafc chia v\u1edbi m\u1ed9t s\u1ed1 \u0111\u1ec3 gi\u1ea3i.","explain":"<span class='basic_left'>Ta c\u00f3:<br\/> $3x + 8 > 2x$<br\/>$\\Leftrightarrow 3x - 2x > -8$ (Chuy\u1ec3n v\u1ebf $2x$; $8$ v\u00e0 \u0111\u1ed5i d\u1ea5u th\u00e0nh $-2x$ ; $-8$)<br\/>$\\Leftrightarrow x > -8$<br\/>V\u1eady t\u1eadp nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $\\left\\{x \\mid x > -8\\right\\}$ <br\/>\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>A. $\\left\\{x \\mid x > -8\\right\\}$<\/span><\/span>","column":2}]}],"id_ques":1106},{"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":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai26/lv1/img\/7.jpg' \/><\/center><br\/>Gi\u1ea3i b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $\\dfrac{2}{5}x > -4$","select":[" A. $\\left\\{x \\mid x > 10\\right\\}$"," B. $\\left\\{x \\mid x < -10\\right\\}$","C. $\\left\\{x \\mid x < 10 \\right\\}$","D. $\\left\\{x \\mid x > -10 \\right\\}$"],"hint":"S\u1eed d\u1ee5ng quy t\u1eafc nh\u00e2n ho\u1eb7c quy t\u1eafc chia v\u1edbi m\u1ed9t s\u1ed1 \u0111\u1ec3 gi\u1ea3i.","explain":"<span class='basic_left'>Ta c\u00f3:<br\/> $\\dfrac{2}{5}x > -4$<br\/>$\\Leftrightarrow \\dfrac{2}{5}x. \\dfrac{5}{2} > -4. \\dfrac{5}{2}$ (Nh\u00e2n c\u1ea3 hai v\u1ebf v\u1edbi $ \\dfrac{5}{2}$)<br\/>$\\Leftrightarrow x > -10$<br\/>V\u1eady t\u1eadp nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $\\left\\{x \\mid x > -10\\right\\}$ <br\/>\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>D. $\\left\\{x \\mid x > -10\\right\\}$<\/span><\/span>","column":2}]}],"id_ques":1107},{"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":"H\u00ecnh v\u1ebd sau bi\u1ec3u di\u1ec5n t\u1eadp nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh n\u00e0o?<br\/><center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai26/lv1/img\/D8C4B2_D101.png' \/><\/center>","select":[" A. $2x < 10$"," B. $x + 6 > 11$","C. $-x + 5 < 10$","D. $x - 4 < -9$"],"hint":"","explain":"<span class='basic_left'>Ta c\u00f3: <br\/>H\u00ecnh v\u1ebd tr\u00ean bi\u1ec3u di\u1ec5n t\u1eadp h\u1ee3p $\\left\\{x \\mid x < 5\\right\\}$<br\/>L\u1ea1i c\u00f3:<br\/>+) $2x < 10$ $\\Leftrightarrow 2x : 2 < 10 : 2$ $\\Leftrightarrow x < 5$ <b>(\u0111\u00e1p \u00e1n A \u0111\u00fang)<\/b><br\/>+) $x + 6 > 11$ $\\Leftrightarrow x > 11 - 6$ $\\Leftrightarrow x > 5$ <b>(\u0111\u00e1p \u00e1n B sai)<\/b><br\/>+) $-x + 5 < 10$ $\\Leftrightarrow x > 5 - 10$ $\\Leftrightarrow x > -5$ <b>(\u0111\u00e1p \u00e1n C sai)<\/b><br\/>+) $x - 4 < -9$ $\\Leftrightarrow x < -9 + 4$ $\\Leftrightarrow x < -5$ <b>(\u0111\u00e1p \u00e1n D sai)<\/b><br\/> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>A. $2x < 10$<\/span><\/span>","column":2}]}],"id_ques":1108},{"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":"H\u00ecnh v\u1ebd sau bi\u1ec3u di\u1ec5n t\u1eadp nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh n\u00e0o?<br\/><center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai26/lv1/img\/D8C4B2_D102.png' \/><\/center>","select":[" A. $x - 3 > 7$"," B. $2x + 1 > 9$","C. $x + 5 > 1$","D. $3x - 5 > 7$"],"hint":"","explain":"<span class='basic_left'>Ta c\u00f3: <br\/>H\u00ecnh v\u1ebd tr\u00ean bi\u1ec3u di\u1ec5n t\u1eadp h\u1ee3p $\\left\\{x \\mid x > -4\\right\\}$<br\/>L\u1ea1i c\u00f3:<br\/>+) $x - 3 > 7$ $\\Leftrightarrow x > 7 + 3$ $\\Leftrightarrow x > 10$ <b>(\u0111\u00e1p \u00e1n A sai)<\/b><br\/>+) $2x + 1 > 9$ $\\Leftrightarrow 2x > 9 - 1$ $\\Leftrightarrow 2x > 8$ $\\Leftrightarrow 2x : 2 > 8 : 2$ $\\Leftrightarrow x > 4$ <b>(\u0111\u00e1p \u00e1n B sai)<\/b><br\/>+) $x + 5 > 1$ $\\Leftrightarrow x > 1 - 5$ $\\Leftrightarrow x > -4$ <b>(\u0111\u00e1p \u00e1n C \u0111\u00fang)<\/b><br\/>+) $3x - 5 > 7$ $\\Leftrightarrow 3x > 7 + 5$ $\\Leftrightarrow 3x > 12 \\Leftrightarrow 3x : 3 > 12 : 3 \\Leftrightarrow x > 4$ <b>(\u0111\u00e1p \u00e1n D sai)<\/b><br\/> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>C. $x + 5 > 1$<\/span><\/span>","column":2}]}],"id_ques":1109},{"time":24,"part":[{"title":"Ch\u1ecdn <u>nh\u1eefng<\/u> \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"Ch\u1ecdn \u0111\u01b0\u1ee3c nhi\u1ec1u \u0111\u00e1p \u00e1n","temp":"checkbox","correct":[["1","2"]],"list":[{"point":5,"img":"","ques":"<span class='basic_left'>Trong c\u00e1c b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh sau, h\u00e3y cho bi\u1ebft b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh n\u00e0o l\u00e0 b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc nh\u1ea5t m\u1ed9t \u1ea9n.<br\/><b>H\u00e3y ch\u1ecdn nh\u1eefng \u0111\u00e1p \u00e1n \u0111\u00fang<\/b><\/span>","hint":"","column":2,"number_true":2,"select":["A. $x + 3 > 5$","B. $3x - 8 \\geq 7$","C. $0.x + 9 > 0$","D. $x^2 = 4$"],"explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>B\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh d\u1ea1ng $ax + b < 0$ (ho\u1eb7c $ax + b > 0; ax + b \\leq 0; ax + b \\geq 0$) trong \u0111\u00f3 $a$ v\u00e0 $b$ l\u00e0 hai s\u1ed1 \u0111\u00e3 cho, $a \\neq 0$, \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc nh\u1ea5t m\u1ed9t \u1ea9n.<\/span> <br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3: <br\/>+ $x + 3 > 5 \\Leftrightarrow x + 3 - 5 > 0 \\Leftrightarrow x - 2 > 0$ <b> (\u0111\u00e1p \u00e1n A \u0111\u00fang)<\/b><br\/>+ $3x - 8 \\geq 7 \\Leftrightarrow 3x - 8 - 7 \\geq 0 \\Leftrightarrow 3x - 15 \\geq 0 $ <b> (\u0111\u00e1p \u00e1n B \u0111\u00fang)<\/b><br\/> + \u0110\u00e1p \u00e1n C sai v\u00ec $a = 0$<br\/>+ \u0110\u00e1p \u00e1n D sai v\u00ec $x$ c\u00f3 s\u1ed1 m\u0169 l\u00e0 $2$<br\/>V\u1eady c\u00e1c \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>A; B<\/span><\/span> <br\/><\/span><br\/> "}]}],"id_ques":1110},{"time":24,"part":[{"title":"Ch\u1ecdn <u>nh\u1eefng<\/u> \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"Ch\u1ecdn \u0111\u01b0\u1ee3c nhi\u1ec1u \u0111\u00e1p \u00e1n","temp":"checkbox","correct":[["1","2"]],"list":[{"point":5,"img":"","ques":"<span class='basic_left'>Trong c\u00e1c b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh sau, h\u00e3y cho bi\u1ebft b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh n\u00e0o l\u00e0 b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc nh\u1ea5t m\u1ed9t \u1ea9n.<br\/><b>H\u00e3y ch\u1ecdn nh\u1eefng \u0111\u00e1p \u00e1n \u0111\u00fang<\/b><\/span>","hint":"","column":2,"number_true":2,"select":["A. $x - 5 > 0$","B. $8x - 15 \\geq 0$","C. $0.x + 4 > 0$","D. $x^2 + 1 > 9$"],"explain":"<span class='basic_left'>B\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh d\u1ea1ng $ax + b < 0$ (ho\u1eb7c $ax + b > 0; ax + b \\leq 0; ax + b \\geq 0$) trong \u0111\u00f3 $a$ v\u00e0 $b$ l\u00e0 hai s\u1ed1 \u0111\u00e3 cho, $a \\neq 0$, \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc nh\u1ea5t m\u1ed9t \u1ea9n.<br\/>Do \u0111\u00f3 c\u00e1c \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>A. $x - 5 > 0$; B. $8x - 15 \\geq 0$ <\/span><\/span> "}]}],"id_ques":1111},{"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":"<span class='basic_left'>H\u00e3y l\u1eadp b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh cho b\u00e0i to\u00e1n sau:<br\/>Qu\u00e3ng \u0111\u01b0\u1eddng t\u1eeb $A$ \u0111\u1ebfn $B$ d\u00e0i $40km$. M\u1ed9t \u00f4 t\u00f4 \u0111i t\u1eeb $A$ \u0111\u1ebfn $B$, kh\u1edfi h\u00e0nh l\u00fac $6$ gi\u1edd. H\u1ecfi \u00f4 t\u00f4 ph\u1ea3i \u0111i v\u1edbi v\u1eadn t\u1ed1c bao nhi\u00eau ki-l\u00f4-m\u00e9t \u0111\u1ec3 \u0111\u1ebfn $B$ tr\u01b0\u1edbc $8$ gi\u1edd c\u00f9ng ng\u00e0y?<\/span>","select":[" A. $\\dfrac{40}{x} < 2$"," B. $\\dfrac{40}{x} > 2$","C. $\\dfrac{40}{x} < 6$","D. $\\dfrac{40}{x} > 8$"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>Ph\u01b0\u01a1ng ph\u00e1p gi\u1ea3i:<\/span><br\/> D\u1ef1a v\u00e0o d\u1eef ki\u1ec7n \u0111\u00e3 cho trong b\u00e0i to\u00e1n \u0111\u1ec3 ch\u1ecdn \u1ea9n s\u1ed1 $x$ r\u1ed3i d\u1ef1a v\u00e0o m\u1ed1i quan h\u1ec7 gi\u1eefa gi\u1ea3 thi\u1ebft c\u1ee7a b\u00e0i to\u00e1n v\u1edbi k\u1ebft lu\u1eadn c\u1ea7n t\u00ecm \u0111\u1ec3 l\u1eadp b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh.<\/span> <br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> G\u1ecdi $x$ ($km\/h$) l\u00e0 v\u1eadn t\u1ed1c c\u1ee7a \u00f4t\u00f4 ($x > 0$)<br\/>V\u00ec qu\u00e3ng \u0111\u01b0\u1eddng t\u1eeb $A$ \u0111\u1ebfn $B$ d\u00e0i $40km$ n\u00ean th\u1eddi gian \u00f4t\u00f4 \u0111i t\u1eeb $A$ \u0111\u1ebfn $B$ l\u00e0: $\\dfrac{40}{x}$ (gi\u1edd)<br\/>V\u00ec ph\u1ea3i \u0111\u1ebfn $B$ tr\u01b0\u1edbc $8$ gi\u1edd n\u00ean th\u1eddi gian \u00f4 t\u00f4 \u0111i t\u1eeb $A$ \u0111\u1ebfn $B$ ph\u1ea3i nh\u1ecf h\u01a1n $2$ gi\u1edd. Ta c\u00f3 b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh: $\\dfrac{40}{x} < 2$<br\/>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>A. $\\dfrac{40}{x} < 2$<\/span>","column":2}]}],"id_ques":1112},{"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":"<span class='basic_left'>H\u00e3y l\u1eadp b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh cho b\u00e0i to\u00e1n sau:<br\/>T\u00ecm m\u1ed9t s\u1ed1 bi\u1ebft r\u1eb1ng t\u1ed5ng hai l\u1ea7n s\u1ed1 \u0111\u00f3 v\u00e0 $5$ nh\u1ecf h\u01a1n $8$.<\/span>","select":[" A. $x + 5 < 8$"," B. $2 + 5x < 8$","C. $2x + 5 < 8$","D. $2x < 8$"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>Ph\u01b0\u01a1ng ph\u00e1p gi\u1ea3i:<\/span><br\/> D\u1ef1a v\u00e0o d\u1eef ki\u1ec7n \u0111\u00e3 cho trong b\u00e0i to\u00e1n \u0111\u1ec3 ch\u1ecdn \u1ea9n s\u1ed1 $x$ r\u1ed3i d\u1ef1a v\u00e0o m\u1ed1i quan h\u1ec7 gi\u1eefa gi\u1ea3 thi\u1ebft c\u1ee7a b\u00e0i to\u00e1n v\u1edbi k\u1ebft lu\u1eadn c\u1ea7n t\u00ecm \u0111\u1ec3 l\u1eadp b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh.<\/span> <br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> G\u1ecdi s\u1ed1 c\u1ea7n t\u00ecm l\u00e0 $x$<br\/>Theo \u0111\u1ec1 b\u00e0i ta c\u00f3: $2x + 5 < 8$<br\/>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>C. $2x + 5 < 8$<\/span><\/span> <br\/><\/span><br\/>","column":2}]}],"id_ques":1113},{"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":"<span class='basic_left'>Ki\u1ec3m tra xem gi\u00e1 tr\u1ecb $x = 2$ l\u00e0 nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh n\u00e0o trong c\u00e1c b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh sau:<\/span>","select":[" A. $2x + 5 < 8$"," B. $3x + 8 > 15$","C. $4x - 5 > 4$","D. $x + 9 > 10$"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>Ph\u01b0\u01a1ng ph\u00e1p gi\u1ea3i:<\/span><br\/> Thay $x = a$ v\u00e0o hai v\u1ebf c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh:<br\/>+ N\u1ebfu \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00fang th\u00ec $x = a$ l\u00e0 nghi\u1ec7m<br\/>+ N\u1ebfu kh\u00f4ng \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00fang th\u00ec $x = a$ kh\u00f4ng l\u00e0 nghi\u1ec7m. <\/span> <br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> + Thay $x = 2$ v\u00e0o b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $2x + 5 < 8$, ta \u0111\u01b0\u1ee3c:<br\/>$VT = 2.2 + 5 = 9$; $VP = 8$<br\/>L\u1ea1i c\u00f3: $9 > 8$ n\u00ean $x = 2$ kh\u00f4ng l\u00e0 nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh<br\/>+ Thay $x = 2$ v\u00e0o b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $3x + 8 > 15$, ta \u0111\u01b0\u1ee3c:<br\/>$VT = 3.2 + 8 = 14$; $VP = 15$<br\/>L\u1ea1i c\u00f3: $14 < 15$ n\u00ean $x = 2$ kh\u00f4ng l\u00e0 nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh<br\/>+ Thay $x = 2$ v\u00e0o b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $4x - 5 > 4$, ta \u0111\u01b0\u1ee3c:<br\/>$VT = 4.2 - 5 = 3$; $VP = 4$<br\/>L\u1ea1i c\u00f3: $3 < 4$ n\u00ean $x = 2$ kh\u00f4ng l\u00e0 nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh<br\/>+ Thay $x = 2$ v\u00e0o b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $x + 9 > 10$, ta \u0111\u01b0\u1ee3c:<br\/>$VT = 2 + 9 = 11$; $VP = 10$<br\/>L\u1ea1i c\u00f3: $11 > 10$ n\u00ean $x = 2$ l\u00e0 nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh<br\/>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>D. $x + 9 > 10$<\/span>","column":2}]}],"id_ques":1114},{"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":"<span class='basic_left'>Ki\u1ec3m tra xem gi\u00e1 tr\u1ecb $x = 5$ l\u00e0 nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh n\u00e0o trong c\u00e1c b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh sau:<\/span>","select":[" A. $x - 8 > 2x - 13$"," B. $-x - 5 > 2x - 19$","C. $x + 3 > 2x - 6$","D. $x + 4 > 12$"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>Ph\u01b0\u01a1ng ph\u00e1p gi\u1ea3i:<\/span><br\/> Thay $x = a$ v\u00e0o hai v\u1ebf c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh:<br\/>+ N\u1ebfu \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00fang th\u00ec $x = a$ l\u00e0 nghi\u1ec7m<br\/>+ N\u1ebfu kh\u00f4ng \u0111\u01b0\u1ee3c b\u1ea5t \u0111\u1eb3ng th\u1ee9c \u0111\u00fang th\u00ec $x = a$ kh\u00f4ng l\u00e0 nghi\u1ec7m. <\/span> <br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> + Thay $x = 5$ v\u00e0o b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $x - 8 > 2x - 13$, ta \u0111\u01b0\u1ee3c:<br\/>$VT = 5 - 8 = -3$; $VP = 2.5 - 13 = -3$<br\/>L\u1ea1i c\u00f3: $-3 = -3$ n\u00ean $x = 5$ kh\u00f4ng l\u00e0 nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh<br\/>+ Thay $x = 5$ v\u00e0o b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $-x - 5 > 2x - 19$, ta \u0111\u01b0\u1ee3c:<br\/>$VT = -5 - 5 = -10$; $VP = 2.5 - 19 = -9$<br\/>L\u1ea1i c\u00f3: $-10 < -9$ n\u00ean $x = 5$ kh\u00f4ng l\u00e0 nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh<br\/>+ Thay $x = 5$ v\u00e0o b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $x + 3 > 2x - 6$, ta \u0111\u01b0\u1ee3c:<br\/>$VT = 5 + 3 = 8$; $VP = 2.5 - 6 = 4$<br\/>L\u1ea1i c\u00f3: $8 > 4$ n\u00ean $x = 5$ l\u00e0 nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh<br\/>+ Thay $x = 5$ v\u00e0o b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $x +4 > 12$, ta \u0111\u01b0\u1ee3c:<br\/>$VT = 5 + 4 = 9$; $VP = 12$<br\/>L\u1ea1i c\u00f3: $9 < 12$ n\u00ean $x = 5$ kh\u00f4ng l\u00e0 nghi\u1ec7m c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh<br\/>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>C. $x + 3 > 2x - 6$<\/span>","column":2}]}],"id_ques":1115},{"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":"<span class='basic_left'>B\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $x + 4 > 7$ v\u00e0 $2x - 3 > 3$ l\u00e0 hai b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh t\u01b0\u01a1ng \u0111\u01b0\u01a1ng. <b>\u0110\u00fang<\/b> hay <b> Sai<\/b>?<\/span>","select":[" A. \u0110\u00fang"," B. Sai"],"hint":"Hai b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh g\u1ecdi l\u00e0 t\u01b0\u01a1ng \u0111\u01b0\u01a1ng n\u1ebfu ch\u00fang c\u00f3 c\u00f9ng t\u1eadp nghi\u1ec7m.","explain":"<span class='basic_left'>Ta c\u00f3: <br\/>+) $x + 4 > 7 \\Leftrightarrow x > 7 - 4 \\Leftrightarrow x > 3$<br\/>+) $2x - 3 > 3 \\Leftrightarrow 2x > 3 + 3 \\Leftrightarrow 2x > 6 \\Leftrightarrow 2x : 2 > 6 : 2 \\Leftrightarrow x > 3$ <br\/>V\u1eady $x + 4 > 7 \\Leftrightarrow 2x - 3 > 3$ v\u00ec hai b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 c\u00f9ng t\u1eadp nghi\u1ec7m $\\left\\{x \\mid x > 3\\right\\}$<br\/>Ta ch\u1ecdn \u0111\u00e1p \u00e1n <span class='basic_pink'>A. \u0110\u00fang<\/span><\/span>","column":2}]}],"id_ques":1116},{"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":"<span class='basic_left'>B\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $-2x - 5 < 7$ v\u00e0 $x + 5 < 11$ l\u00e0 hai b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh t\u01b0\u01a1ng \u0111\u01b0\u01a1ng. <b>\u0110\u00fang<\/b> hay <b> Sai<\/b>?<\/span>","select":[" A. \u0110\u00fang"," B. Sai"],"hint":"Hai b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh g\u1ecdi l\u00e0 t\u01b0\u01a1ng \u0111\u01b0\u01a1ng n\u1ebfu ch\u00fang c\u00f3 c\u00f9ng t\u1eadp nghi\u1ec7m.","explain":"<span class='basic_left'>Ta c\u00f3: <br\/>+) $-2x - 5 < 7 \\Leftrightarrow -2x < 7 + 5 \\Leftrightarrow -2x < 12 \\Leftrightarrow -2x : (-2) > 12 : (-2) \\Leftrightarrow x > -6$<br\/>+) $x + 5 < 11 \\Leftrightarrow x < 11 - 5 \\Leftrightarrow x < 6$ <br\/>V\u1eady $x + 4 > 7$ kh\u00f4ng t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi $2x - 3 > 3$ v\u00ec hai b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh kh\u00f4ng c\u00f3 c\u00f9ng t\u1eadp nghi\u1ec7m <br\/>Ta ch\u1ecdn \u0111\u00e1p \u00e1n <span class='basic_pink'>B. Sai<\/span><\/span>","column":2}]}],"id_ques":1117},{"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":"<span class='basic_left'>B\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $3x - 5 < 10$ v\u00e0 $x + 4 < 9$ l\u00e0 hai b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh t\u01b0\u01a1ng \u0111\u01b0\u01a1ng. <b>\u0110\u00fang<\/b> hay <b> Sai<\/b>?<\/span>","select":[" A. \u0110\u00fang"," B. Sai"],"hint":"Hai b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh g\u1ecdi l\u00e0 t\u01b0\u01a1ng \u0111\u01b0\u01a1ng n\u1ebfu ch\u00fang c\u00f3 c\u00f9ng t\u1eadp nghi\u1ec7m.","explain":"<span class='basic_left'>Ta c\u00f3: <br\/>+) $3x - 5 < 10 \\Leftrightarrow 3x < 10 + 5 \\Leftrightarrow 3x < 15 \\Leftrightarrow 3x : 3 < 15 : 3 \\Leftrightarrow x < 5$<br\/>+) $x + 4 < 9 \\Leftrightarrow x < 9 - 4 \\Leftrightarrow x < 5$ <br\/>V\u1eady $3x - 5 < 10 \\Leftrightarrow x + 4 < 9$ v\u00ec hai b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 c\u00f9ng t\u1eadp nghi\u1ec7m $\\left\\{x \\mid x < 5\\right\\}$<br\/>Ta ch\u1ecdn \u0111\u00e1p \u00e1n <span class='basic_pink'>A. \u0110\u00fang<\/span><\/span>","column":2}]}],"id_ques":1118},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n th\u00edch h\u1ee3p \u0111\u1ec3 \u0111i\u1ec1n v\u00e0o ch\u1ed7 (...)","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"<span class='basic_left'>Khi chuy\u1ec3n m\u1ed9t h\u1ea1ng t\u1eed c\u1ee7a b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh t\u1eeb v\u1ebf n\u00e0y sang v\u1ebf kia ta ph\u1ea3i ........... h\u1ea1ng t\u1eed \u0111\u00f3<\/span>","select":[" A. \u0111\u1ed5i d\u1ea5u"," B. gi\u1eef nguy\u00ean d\u1ea5u","C. \u0111\u1ed5i th\u00e0nh d\u1ea5u d\u01b0\u01a1ng","D. \u0111\u1ed5i th\u00e0nh d\u1ea5u \u00e2m"],"hint":"","explain":"\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>A. \u0111\u1ed5i d\u1ea5u<\/span>","column":2}]}],"id_ques":1119},{"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/lop8/toan/daiso/bai26/lv1/img\/4.jpg' \/><\/center><br\/>Gi\u1ea3i b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh $\\dfrac{-2}{7}x > -8$","select":[" A. $\\left\\{x \\mid x > -28\\right\\}$"," B. $\\left\\{x \\mid x < -28\\right\\}$","C. $\\left\\{x \\mid x < 28 \\right\\}$","D. $\\left\\{x \\mid x > 28 \\right\\}$"],"hint":"S\u1eed d\u1ee5ng quy t\u1eafc nh\u00e2n ho\u1eb7c quy t\u1eafc chia v\u1edbi m\u1ed9t s\u1ed1 \u0111\u1ec3 gi\u1ea3i.","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$\\dfrac{-2}{7}x > -8$<br\/>$\\Leftrightarrow \\dfrac{-2}{7}x. \\dfrac{-7}{2} < -8. \\dfrac{-7}{2}$ (Nh\u00e2n c\u1ea3 hai v\u1ebf v\u1edbi $ \\dfrac{-7}{2}$)<br\/>$\\Leftrightarrow x < 28$<br\/>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 <span class='basic_pink'>C. $\\left\\{x \\mid x < 28\\right\\}$<\/span><\/span><\/span>","column":2}]}],"id_ques":1120}],"lesson":{"save":0,"level":1}}