{"segment":[{"time":24,"part":[{"title":"Ch\u1ecdn <i>nh\u1eefng<\/i> \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"Ch\u1ecdn \u0111\u01b0\u1ee3c nhi\u1ec1u \u0111\u00e1p \u00e1n","temp":"checkbox","correct":[["1","6","7","8"]],"list":[{"point":5,"img":"","ques":"Trong c\u00e1c ph\u01b0\u01a1ng tr\u00ecnh sau ph\u01b0\u01a1ng tr\u00ecnh n\u00e0o l\u00e0 ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc nh\u1ea5t m\u1ed9t \u1ea9n?","hint":"","column":2,"number_true":2,"select":["A. $1=3x-2$","B. $2x-3y=5$","C. $x^2+x=1$","D. $0.x+3=0$","E. $x^2+y^2=0$","F. $3x=0$","G. $\\dfrac {x-1}{2}=\\dfrac {1}{2}$","H. $\\dfrac{x}{3}-\\dfrac{1}{2}=0$"],"explain":"Ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc nh\u1ea5t m\u1ed9t \u1ea9n l\u00e0 ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 d\u1ea1ng $ax+b=0$. Trong \u0111\u00f3, $a$ v\u00e0 $b$ l\u00e0 c\u00e1c s\u1ed1 cho tr\u01b0\u1edbc v\u00e0 $a\\ne 0$<br\/><span class='basic_pink'>V\u1eady c\u00e1c ph\u01b0\u01a1ng tr\u00ecnh A, F, G, H l\u00e0 c\u00e1c ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc nh\u1ea5t m\u1ed9t \u1ea9n.<\/span>"}]}],"id_ques":991},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00fang hay sai","title_trans":"","temp":"true_false","correct":[["t","f","f","t","f","t"]],"list":[{"point":5,"image":"","col_name":["","\u0110\u00fang","Sai"],"arr_ques":["Ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc nh\u1ea5t m\u1ed9t \u1ea9n lu\u00f4n c\u00f3 m\u1ed9t nghi\u1ec7m duy nh\u1ea5t ","Ph\u01b0\u01a1ng tr\u00ecnh $kx+6=0$ ($k$ l\u00e0 tham s\u1ed1) l\u00e0 ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc nh\u1ea5t m\u1ed9t \u1ea9n","Hai ph\u01b0\u01a1ng tr\u00ecnh t\u01b0\u01a1ng \u0111\u01b0\u01a1ng l\u00e0 hai ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 chung nghi\u1ec7m","Ph\u01b0\u01a1ng tr\u00ecnh ch\u1ee9a \u1ea9n \u1edf m\u1eabu th\u1ee9c c\u00f3 \u0111i\u1ec1u ki\u1ec7n x\u00e1c \u0111\u1ecbnh l\u00e0 t\u1ea5t c\u1ea3 c\u00e1c gi\u00e1 tr\u1ecb c\u1ee7a \u1ea9n sao cho c\u00e1c m\u1eabu th\u1ee9c kh\u00e1c $0$","Ph\u01b0\u01a1ng tr\u00ecnh t\u00edch c\u00f3 d\u1ea1ng $A(x).B(x)=C(x)$ (Trong \u0111\u00f3, $A(x), B(x)$ v\u00e0 $C(x)$ l\u00e0 c\u00e1c \u0111a th\u1ee9c bi\u1ebfn $x$)","T\u1eadp nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 t\u1eadp h\u1ee3p t\u1ea5t c\u1ea3 c\u00e1c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh."],"explain":["<span class='basic_left'>\u0110\u00fang v\u00ec ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc nh\u1ea5t m\u1ed9t \u1ea9n l\u00e0 ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 d\u1ea1ng $ax+b=0$ ($a\\ne 0$) lu\u00f4n c\u00f3 m\u1ed9t nghi\u1ec7m duy nh\u1ea5t l\u00e0 $x=\\dfrac {-b}{a}$<\/span>","<span class='basic_left'><br\/>Sai v\u00ec ph\u01b0\u01a1ng tr\u00ecnh $kx+6=0$ l\u00e0 ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc nh\u1ea5t m\u1ed9t \u1ea9n khi $k\\ne 0$<\/span>","<span class='basic_left'><br\/>Sai v\u00ec hai ph\u01b0\u01a1ng tr\u00ecnh t\u01b0\u01a1ng \u0111\u01b0\u01a1ng l\u00e0 hai ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 c\u00f9ng t\u1eadp nghi\u1ec7m kh\u00f4ng ph\u1ea3i l\u00e0 hai ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 chung nghi\u1ec7m.<\/span>","","<span class='basic_left'><br\/>Sai v\u00ec ph\u01b0\u01a1ng tr\u00ecnh t\u00edch l\u00e0 ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 d\u1ea1ng $A(x)B(x)=0$<\/span>",""]}]}],"id_ques":992},{"time":24,"part":[{"time":3,"title":"N\u1ed1i m\u1ed7i ph\u01b0\u01a1ng tr\u00ecnh c\u1ed9t tr\u00e1i v\u1edbi ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc nh\u1ea5t m\u1ed9t \u1ea9n t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi n\u00f3 \u1edf c\u1ed9t ph\u1ea3i.","title_trans":"","audio":"","temp":"matching","correct":[["2","3","4","1"]],"list":[{"point":5,"image":"","left":["$2x-3=x+1$","$(x-1)^2=(x+4)^2$","$7(x-2)-(5-x)=0$","$ \\dfrac {x-1}{3}-\\dfrac{2-x}{2}=0$"],"right":["$5x-8=0$ ","$x-4=0$","$10x+15=0$","$8x-19=0$"],"top":100,"hint":"","explain":"<span class='basic_left'>$\\bullet \\,\\,2x-3=x+1\\\\\\Leftrightarrow x-4=0$<br\/>$\\bullet \\,\\,(x-1)^2=(x+4)^2\\\\ \\Leftrightarrow x^2-2x+1=x^2+8x+16\\,\\\\ \\Leftrightarrow 10x+15=0$<br\/>$\\bullet \\,\\,7(x-2)-(5-x)=0\\,\\\\\\Leftrightarrow 7x-14+x-5=0\\,\\\\\\Leftrightarrow 8x-19=0$<br\/>$\\bullet \\,\\,\\dfrac {x-1}{3}-\\dfrac{2-x}{2}=0\\,\\\\\\Leftrightarrow 5x-8=0 $<br\/><\/span>"}]}],"id_ques":993},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0110\u00fang ho\u1eb7c Sai","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai22/lv1/img\/12.jpg' \/><\/center>Ph\u01b0\u01a1ng tr\u00ecnh $(x-2)(x-3)=(x-2)(2x+1)$ c\u00f3 t\u1eadp nghi\u1ec7m $S=\\{-4\\}.$","select":["\u0110\u00fang","Sai"],"hint":"","explain":" <span class='basic_left'>Ta c\u00f3:<br\/>$\\begin{aligned} & \\left( x-2 \\right)\\left( x-3 \\right)=\\left( x-2 \\right)\\left( 2x+1 \\right) \\\\ & \\Leftrightarrow \\left( x-2 \\right)\\left[ \\left( x-3 \\right)-\\left( 2x+1 \\right) \\right]=0 \\\\ & \\Leftrightarrow \\left( x-2 \\right)\\left( x-3-2x-1 \\right)=0 \\\\ & \\Leftrightarrow \\left( x-2 \\right)\\left( -x-4 \\right)=0 \\\\ & \\Leftrightarrow \\left[ \\begin{aligned} & x=2 \\\\ & x=-4 \\\\ \\end{aligned} \\right. \\\\ \\end{aligned}$<br\/>V\u1eady ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 t\u1eadp nghi\u1ec7m $S=\\{-4;2\\}$<br\/><span class='basic_pink'>V\u1eady kh\u1eb3ng \u0111\u1ecbnh tr\u00ean l\u00e0 sai<\/span><\/span>","column":2}]}],"id_ques":994},{"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/bai22/lv1/img\/13.jpg' \/><\/center>T\u00ecm $k$ \u0111\u1ec3 ph\u01b0\u01a1ng tr\u00ecnh $2k-x=3x-k$ ($k$ l\u00e0 tham s\u1ed1) c\u00f3 m\u1ed9t nghi\u1ec7m $x=2.$","select":["A. $k=\\dfrac{-8}{3}$","B. $k=\\dfrac{3}{8}$","C. $k=\\dfrac{-3}{8}$","D. $k=\\dfrac{8}{3}$"],"hint":"","explain":" <span class='basic_left'>Thay $x= 2$ v\u00e0o ph\u01b0\u01a1ng tr\u00ecnh tr\u00ean. Ta c\u00f3:<br\/>$\\begin{aligned}& 2k-2=3.2-k \\\\ & \\Leftrightarrow 3k-2=6 \\\\ & \\Leftrightarrow 3k=8 \\\\ & \\Leftrightarrow k=\\dfrac{8}{3} \\\\ \\end{aligned}$<br\/>V\u1eady v\u1edbi $k=\\dfrac{8}{3}$ ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 m\u1ed9t nghi\u1ec7m $x=2$<br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D<\/span><\/span>","column":2}]}],"id_ques":995},{"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/bai22/lv1/img\/8.jpg' \/><\/center>T\u00ecm $k$ \u0111\u1ec3 ph\u01b0\u01a1ng tr\u00ecnh $(x-5)(x-k)=(x-k)(x+5)$ ($k$ l\u00e0 tham s\u1ed1) c\u00f3 m\u1ed9t nghi\u1ec7m $x=5.$","select":["A. $k=5$","B. $k=-5$","C. $k=0$","D. $k=1$"],"hint":"","explain":" <span class='basic_left'>Thay $x= 5$ v\u00e0o ph\u01b0\u01a1ng tr\u00ecnh tr\u00ean. Ta c\u00f3:<br\/>$\\begin{align}& \\left( 5-5 \\right)\\left( 5-k \\right)=\\left( 5-k \\right)\\left( 5+5 \\right) \\\\ & \\Leftrightarrow 0\\left( 5-k \\right)=10\\left( 5-k \\right) \\\\ & \\Leftrightarrow 10\\left( 5-k \\right)=0 \\\\ & \\Leftrightarrow k=5 \\\\ \\end{align}$<br\/>V\u1eady v\u1edbi $k=5$ ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 m\u1ed9t nghi\u1ec7m $x=5$<br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A<\/span><\/span>","column":2}]}],"id_ques":996},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0110\u00fang ho\u1eb7c Sai","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai22/lv1/img\/16.jpg' \/><\/center> \u0110i\u1ec1u ki\u1ec7n x\u00e1c \u0111\u1ecbnh c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh $\\dfrac {1}{x^2-1}+\\dfrac {1}{x^2+1}=0$ l\u00e0 $x\\ne 1.$","select":["\u0110\u00fang","Sai"],"hint":"","explain":" <span class='basic_left'>\u0110i\u1ec1u ki\u1ec7n x\u00e1c \u0111\u1ecbnh c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh: <br\/>$\\left\\{ \\begin{aligned} & {{x}^{2}}-1\\ne 0 \\\\ & {{x}^{2}}+1\\ne 0 \\\\ \\end{aligned} \\right.\\Leftrightarrow \\left\\{ \\begin{aligned} & (x-1)(x+1)\\ne 0 \\\\ & {{x}^{2}}\\ne -1 \\\\ \\end{aligned} \\right.\\Leftrightarrow \\left\\{ \\begin{aligned} & x\\ne 1 \\\\ & x\\ne -1 \\\\ \\end{aligned} \\right.$<br\/>V\u1eady \u0111i\u1ec1u ki\u1ec7n x\u00e1c \u0111\u1ecbnh c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $x\\ne 1$ v\u00e0 $x\\ne -1$<br\/><span class='basic_pink'>V\u1eady kh\u1eb3ng \u0111\u1ecbnh tr\u00ean l\u00e0 sai<\/span><\/span>","column":2}]}],"id_ques":997},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0110\u00fang ho\u1eb7c Sai","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai22/lv1/img\/10.jpg' \/><\/center> Ph\u01b0\u01a1ng tr\u00ecnh $\\dfrac{1}{x-2}-\\dfrac{4}{x^2-4}=0$ c\u00f3 t\u1eadp nghi\u1ec7m $S=\\varnothing .$","select":["\u0110\u00fang","Sai"],"hint":"","explain":" <span class='basic_left'>\u0110i\u1ec1u ki\u1ec7n x\u00e1c \u0111\u1ecbnh c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh: $\\left\\{ \\begin {aligned} &x-2\\ne 0\\\\ &x^2-4\\ne 0 \\\\ \\end{aligned}\\right. \\Leftrightarrow \\left\\{ \\begin{aligned} &x\\ne 2\\\\ &x\\ne -2 \\\\ \\end{aligned}\\right.$<br\/>Ta c\u00f3:<br\/>$\\dfrac{1}{x-2}-\\dfrac{4}{x^2-4}=0\\\\ \\Leftrightarrow \\dfrac{x+2}{x^2-4}-\\dfrac{4}{x^2-4}=0\\\\ \\Leftrightarrow \\dfrac{x-2}{x^2-4}=0\\\\\\Rightarrow x-2=0\\\\\\Leftrightarrow x=2\\,\\,\\text{(lo\u1ea1i)}$<br\/>V\u1eady ph\u01b0\u01a1ng tr\u00ecnh \u0111\u00e3 cho v\u00f4 nghi\u1ec7m<br\/><span class='basic_pink'>V\u1eady kh\u1eb3ng \u0111\u1ecbnh tr\u00ean l\u00e0 \u0110\u00fang<\/span><\/span>","column":2}]}],"id_ques":998},{"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":[[["-3"]]],"list":[{"point":5,"width":50,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai22/lv1/img\/16.jpg' \/><\/center>Gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh $(4x+7)(x-5)-3x^2-1=x(x-1).$<br\/>T\u1eadp nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $S=${_input_}","hint":"","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$(4x+7)(x-5)-3x^2-1=x(x-1)\\\\ \\Leftrightarrow 4x^2-20x+7x-35-3x^2-1=x^2-x\\\\ \\Leftrightarrow x^2-13x-36-x^2+x=0\\\\ \\Leftrightarrow -12x-36=0\\\\ \\Leftrightarrow x=-3$<br\/>V\u1eady t\u1eadp nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $S=\\{-3\\}$<br\/><span class='basic_pink'>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $-3$<\/span><\/span>"}]}],"id_ques":999},{"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":[[["-3"]]],"list":[{"point":5,"width":50,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai22/lv1/img\/11.jpg' \/><\/center>Gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh $6x-3+(x-1)^2-(x+1)^2=3x.$<br\/>T\u1eadp nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $S=${_input_}","hint":"","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$6x-3+(x-1)^2-(x+1)^2=3x\\\\ \\Leftrightarrow 6x-3+x^2-2x+1-(x^2+2x+1)-3x=0\\\\ \\Leftrightarrow 6x-3+x^2-2x+1-x^2-2x-1-3x=0\\\\ \\Leftrightarrow -x-3=0\\\\ \\Leftrightarrow x=-3$<br\/>V\u1eady ph\u01b0\u01a1ng tr\u00ecnh \u0111\u00e3 c\u00f3 t\u1eadp nghi\u1ec7m $S=\\{-3\\}$<br\/><span class='basic_pink'>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $-3$<\/span><\/span>"}]}],"id_ques":1000},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 d\u01b0\u1edbi d\u1ea1ng ph\u00e2n s\u1ed1","temp":"fill_the_blank","correct":[[["87"],["43"]]],"list":[{"point":5,"width":50,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai22/lv1/img\/12.jpg' \/><\/center>Gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh $\\dfrac {5x+6}{3}-\\dfrac{3x+1}{4}=\\dfrac{x+16}{5}.$<br\/>T\u1eadp nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $S=${<div class=\"frac123\"><div class=\"ts\">_input_<\/div><div class=\"ms\">_input_<\/div><\/div>}","hint":"","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$\\dfrac {5x+6}{3}-\\dfrac{3x+1}{4}=\\dfrac{x+16}{5}\\\\ \\Leftrightarrow \\dfrac {20(5x+6)}{60}-\\dfrac {15(3x+1)}{60}=\\dfrac{12(x+16)}{60}\\\\ \\Leftrightarrow 20(5x+6)-15(3x+1)=12(x+16)\\\\ \\Leftrightarrow 100x+120-45x-15-12x-192=0\\\\ \\Leftrightarrow 43x-87=0\\\\ \\Leftrightarrow x=\\dfrac{87}{43}$<br\/>V\u1eady ph\u01b0\u01a1ng tr\u00ecnh \u0111\u00e3 c\u00f3 t\u1eadp nghi\u1ec7m $S=\\left\\{\\dfrac{87}{43}\\right\\}$<\/span>"}]}],"id_ques":1001},{"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/bai22/lv1/img\/11.jpg' \/><\/center>Ph\u01b0\u01a1ng tr\u00ecnh $15(3x-1)(2x-2)(x-3)=0$ c\u00f3 t\u1eadp nghi\u1ec7m l\u00e0:","select":["A. $S=\\left\\{\\dfrac{1}{3};1;3\\right\\}$","B. $S=\\left\\{\\dfrac{-1}{3};-1;3\\right\\}$","C. $S=\\left\\{\\dfrac{-1}{3};1;3\\right\\}$","D. $S=\\left\\{\\dfrac{1}{3};2;3\\right\\}$"],"hint":"Gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh t\u00edch, t\u00ecm nghi\u1ec7m r\u1ed3i l\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n.","explain":" <span class='basic_left'>Ta c\u00f3:<br\/>$15(3x-1)(2x-2)(x-3)=0\\\\ \\Leftrightarrow \\left[\\begin{aligned}&3x-1=0\\\\ &2x-2=0\\\\&x-3=0\\\\ \\end {aligned}\\right. \\\\ \\Leftrightarrow \\left[\\begin{aligned}&x=\\dfrac{1}{3}\\\\ &x=1\\\\&x=3\\\\ \\end {aligned}\\right.$<br\/>V\u1eady t\u1eadp nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $S=\\left\\{\\dfrac{1}{3};1;3\\right\\}$<br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A<\/span><\/span>","column":2}]}],"id_ques":1002},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank_random","correct":[[["0"],["-2"]]],"list":[{"point":5,"width":50,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai22/lv1/img\/5.jpg' \/><\/center>Gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh $x^3+2x^2=0.$<br\/>T\u1eadp nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $S=${_input_;_input_}","hint":"Ph\u00e2n t\u00edch v\u1ebf tr\u00e1i th\u00e0nh nh\u00e2n t\u1eed r\u1ed3i gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh","explain":"<span class='basic_left'>Ta c\u00f3:<br\/> $x^3+2x^2=0\\\\ \\Leftrightarrow x^2(x+2)=0\\\\ \\Leftrightarrow \\left[\\begin{aligned} &x^2=0\\\\ &x+2=0\\\\ \\end{aligned}\\right.\\\\ \\Leftrightarrow \\left[\\begin{aligned}&x=0\\\\ &x=-2\\\\ \\end{aligned}\\right.$ <br\/>V\u1eady ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 t\u1eadp nghi\u1ec7m $S=\\{-2;0\\}$<br\/><span class='basic_pink'>V\u1eady c\u00e1c s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o ch\u1ed7 tr\u1ed1ng l\u00e0 $0;-2$<\/span><\/span>"}]}],"id_ques":1003},{"time":24,"part":[{"title":"Ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"select":["A. $\\left[\\begin{aligned}&x=0\\\\ &x=1\\\\ &x=\\dfrac{3}{2}\\\\ \\end{aligned}\\right.$","B. $\\left[\\begin{aligned}&x=-1\\\\ &x=1\\\\ &x=\\dfrac{3}{2}\\\\ \\end{aligned}\\right.$","C. $\\left[\\begin{aligned}&x=1\\\\ &x=2\\\\ &x=\\dfrac{3}{2}\\\\ \\end{aligned}\\right.$"],"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai22/lv1/img\/16.jpg' \/><\/center>Gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh $2x^2-3x=2x^3-3x^2.$<br\/>T\u1eadp nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $S=${?}","hint":"Ph\u00e2n t\u00edch hai v\u1ebf th\u00e0nh nh\u00e2n t\u1eed r\u1ed3i chuy\u1ec3n v\u1ebf","explain":"<span class='basic_left'>Ta c\u00f3:<br\/> $2x^2-3x=2x^3-3x^2\\\\ \\Leftrightarrow x(2x-3)=x^2(2x-3)\\\\ \\Leftrightarrow x(2x-3)-x^2(2x-3)=0\\\\ \\Leftrightarrow (x-x^2)(2x-3)=0\\\\ \\Leftrightarrow x(1-x)(2x-3)=0\\\\ \\Leftrightarrow \\left[\\begin{aligned} &x=0\\\\ &1-x=0\\\\ &2x-3=0\\\\ \\end{aligned}\\right.\\\\ \\Leftrightarrow \\left[\\begin{aligned}&x=0\\\\ &x=1\\\\ &x=\\dfrac{3}{2}\\\\ \\end{aligned}\\right.$ <br\/>V\u1eady ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 t\u1eadp nghi\u1ec7m $S=\\left\\{0;1;\\dfrac{3}{2}\\right\\}$<\/span>"}]}],"id_ques":1004},{"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":[[["-2"]]],"list":[{"point":5,"width":50,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai22/lv1/img\/7.jpg' \/><\/center>Gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh $\\dfrac {4x+5}{x-1}+\\dfrac{2x-1}{x+1}=6.$<br\/>T\u1eadp nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $S=${_input_}","hint":"Bi\u1ebfn \u0111\u1ed5i ph\u01b0\u01a1ng tr\u00ecnh v\u1ec1 d\u1ea1ng ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc nh\u1ea5t m\u1ed9t \u1ea9n.","explain":"<span class='basic_left'>\u0110i\u1ec1u ki\u1ec7n x\u00e1c \u0111\u1ecbnh: $x\\ne 1$ v\u00e0 $x\\ne -1$<br\/>Ta c\u00f3:<br\/>$\\dfrac {4x+5}{x-1}+\\dfrac{2x-1}{x+1}=6\\\\ \\Leftrightarrow \\dfrac {(4x+5)(x+1)}{(x-1)(x+1)}+\\dfrac{(2x-1)(x-1)}{(x+1)(x-1)}=\\dfrac{6(x-1)(x+1)}{(x-1)(x+1)}\\\\ \\Rightarrow (4x+5)(x+1)+(2x-1)(x-1)=6(x+1)(x-1)\\\\ \\Leftrightarrow 4x^2+9x+5+2x^2-3x+1=6(x^2-1)\\\\ \\Leftrightarrow 4x^2+9x+5+2x^2-3x+1-6x^2+6=0\\\\ \\Leftrightarrow 6x+12=0\\\\ \\Leftrightarrow x=-2\\,\\,\\text{(th\u1ecfa m\u00e3n)}$ <br\/>V\u1eady ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 t\u1eadp nghi\u1ec7m $S=\\{-2\\}$<br\/><span class='basic_pink'>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o ch\u1ed7 tr\u1ed1ng l\u00e0 $-2$<\/span><\/span>"}]}],"id_ques":1005},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 d\u01b0\u1edbi d\u1ea1ng ph\u00e2n s\u1ed1","temp":"fill_the_blank","correct":[[["9"],["7"]]],"list":[{"point":5,"width":50,"type_input":"","input_hint":"frac","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai22/lv1/img\/8.jpg' \/><\/center>Gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh $\\dfrac {8}{x+1}+\\dfrac {1}{x-1}=\\dfrac {9}{x}.$<br\/>T\u1eadp nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh l\u00e0 $S=${<div class=\"frac123\"><div class=\"ts\">_input_<\/div><div class=\"ms\">_input_<\/div><\/div>}","hint":"","explain":"<span class='basic_left'>\u0110i\u1ec1u ki\u1ec7n x\u00e1c \u0111\u1ecbnh: $\\left\\{\\begin{align}&x\\ne 0\\\\ &x\\ne -1\\\\ &x\\ne 1\\\\ \\end{align}\\right.$<br\/>Ta c\u00f3:<br\/>$\\dfrac {8}{x+1}+\\dfrac {1}{x-1}=\\dfrac {9}{x}\\\\ \\Leftrightarrow \\dfrac {8x(x-1)}{x(x-1)(x+1)}+\\dfrac{x(x+1)}{x(x+1)(x-1)}=\\dfrac{9(x-1)(x+1)}{x(x-1)(x+1)}\\\\ \\Rightarrow 8x(x-1)+x(x+1)=9(x-1)(x+1)\\\\ \\Leftrightarrow 8x^2-8x+x^2+x=9(x^2-1)\\\\ \\Leftrightarrow 8x^2-8x+x^2+x-9x^2+9=0\\\\ \\Leftrightarrow -7x+9=0\\\\ \\Leftrightarrow x=\\dfrac{9}{7}\\,\\,\\text{(th\u1ecfa m\u00e3n)}$ <br\/>V\u1eady ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 t\u1eadp nghi\u1ec7m $S=\\left\\{\\dfrac{9}{7}\\right\\}$<\/span>"}]}],"id_ques":1006},{"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/bai22/lv1/img\/12.jpg' \/><\/center>L\u00fac $6$ gi\u1edd, m\u1ed9t xe m\u00e1y kh\u1edfi h\u00e0nh t\u1eeb $A$ \u0111\u1ebfn $B$. Sau $2$ gi\u1edd, m\u1ed9t \u00f4 t\u00f4 c\u0169ng kh\u1edfi h\u00e0nh t\u1eeb $A$ \u0111\u1ebfn $B$ v\u1edbi v\u1eadn t\u1ed1c l\u1edbn h\u01a1n v\u1eadn t\u1ed1c xe m\u00e1y $20$ $km\/h$. Do v\u1eady, \u0111\u1ebfn $10$ gi\u1edd $30$ ph\u00fat c\u1ea3 hai xe c\u00f9ng \u0111\u1ebfn $B$. T\u00ednh qu\u00e3ng \u0111\u01b0\u1eddng $AB$.","select":["A. $112,5\\,km$","B. $25\\,km$","C. $55\\,km$","D. $110,2\\,km$"],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn<\/span><br\/><table><tr><th><\/th><th>Qu\u00e3ng \u0111\u01b0\u1eddng ($km$)<\/th><th>V\u1eadn t\u1ed1c $(km\/h)$<\/th><th>Th\u1eddi gian (gi\u1edd)<\/th><\/tr><tr><td>Xe m\u00e1y<\/td><td>$x$<\/td><td>$\\dfrac{2x}{9}$<\/td><td>$\\dfrac{9}{2}$<\/td><\/tr><tr><td>\u00d4 t\u00f4<\/td><td>$x$<\/td><td>$\\dfrac{2x}{5}$<\/td><td>$\\dfrac{5}{2}$<\/td><\/tr><\/table><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i<\/span><br\/>G\u1ecdi qu\u00e3ng \u0111\u01b0\u1eddng $AB$ l\u00e0 $x$ ($km$, $x>0$)<br\/>V\u00ec xe m\u00e1y \u0111i t\u1eeb $6$ gi\u1edd \u0111\u1ebfn $B$ l\u00fac $10$ gi\u1edd $30$ ph\u00fat n\u00ean th\u1eddi gian xe m\u00e1y \u0111i h\u1ebft qu\u00e3ng \u0111\u01b0\u1eddng $AB$ l\u00e0 $4$ gi\u1edd $30$ ph\u00fat $=\\dfrac{9}{2}$ gi\u1edd<br\/>Do \u0111\u00f3, v\u1eadn t\u1ed1c c\u1ee7a xe m\u00e1y l\u00e0 $x:\\dfrac {9}{2}=\\dfrac{2x}{9}$($km\/h$) <br\/>V\u00ec \u00f4 t\u00f4 \u0111i sau xe m\u00e1y $2$ gi\u1edd m\u00e0 l\u1ea1i \u0111\u1ebfn $B$ c\u00f9ng xe m\u00e1y n\u00ean th\u1eddi gian \u00f4 t\u00f4 \u0111i h\u1ebft qu\u00e3ng \u0111\u01b0\u1eddng $AB$ l\u00e0 $\\dfrac {9}{2}-2=\\dfrac {5}{2}$ (gi\u1edd).<br\/>Do \u0111\u00f3, v\u1eadn t\u1ed1c c\u1ee7a \u00f4 t\u00f4 l\u00e0 $x: \\dfrac{5}{2}=\\dfrac{2x}{5}$ ($km\/h$)<br\/>V\u00ec v\u1eadn t\u1ed1c \u00f4 t\u00f4 l\u1edbn h\u01a1n v\u1eadn t\u1ed1c xe m\u00e1y $20 km\/h$ n\u00ean ta c\u00f3 ph\u01b0\u01a1ng tr\u00ecnh: <br\/>$\\dfrac{2x}{9}+20=\\dfrac{2x}{5}\\\\ \\Leftrightarrow \\dfrac{10x}{9}+\\dfrac{900}{45}=\\dfrac{18x}{45}\\\\ \\Leftrightarrow 10x+900=18x\\\\ \\Leftrightarrow x=112,5\\,\\,\\text{(th\u1ecfa m\u00e3n)}$<br\/>V\u1eady qu\u00e3ng \u0111\u01b0\u1eddng $AB$ d\u00e0i l\u00e0 $112,5$ $km$<br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A<\/span><br\/>Ngo\u00e0i c\u00e1ch g\u1ecdi \u1ea9n tr\u00ean ta c\u00f3 th\u1ec3 gi\u1ea3i b\u00e0i to\u00e1n b\u1eb1ng c\u00e1ch g\u1ecdi v\u1eadn t\u1ed1c xe m\u00e1y l\u00e0 \u1ea9n v\u00e0 l\u1eadp ph\u01b0\u01a1ng tr\u00ecnh:<br\/><table><tr><th><\/th><th>Qu\u00e3ng \u0111\u01b0\u1eddng ($km$)<\/th><th>V\u1eadn t\u1ed1c $(km\/h)$<\/th><th>Th\u1eddi gian (gi\u1edd)<\/th><\/tr><tr><td>Xe m\u00e1y<\/td><td>$\\dfrac{9}{2}.x$<\/td><td>$x$<\/td><td>$\\dfrac{9}{2}$<\/td><\/tr><tr><td>\u00d4 t\u00f4<\/td><td>$(x+20)\\dfrac{5}{2}$<\/td><td>$x+20$<\/td><td>$\\dfrac{5}{2}$<\/td><\/tr><\/table><br\/>Ta c\u00f3 ph\u01b0\u01a1ng tr\u00ecnh: $\\dfrac{9}{2}.x=(x+20)\\dfrac{5}{2}$<\/span>","column":2}]}],"id_ques":1007},{"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":[[["3"]]],"list":[{"point":5,"width":50,"type_input":"","ques":"<span class='basic_left'>Qu\u00e3ng \u0111\u01b0\u1eddng $AB$ d\u00e0i $190 km$. M\u1ed9t \u00f4 t\u00f4 kh\u1edfi h\u00e0nh t\u1eeb $A$ \u0111\u1ebfn $B$ v\u1edbi v\u1eadn t\u1ed1c $50 km$. Sau $2$ gi\u1edd, m\u1ed9t xe m\u00e1y kh\u1edfi h\u00e0nh t\u1eeb $B$ v\u1ec1 $A$ v\u1edbi v\u1eadn t\u1ed1c $40 km\/h$. H\u1ecfi sau bao l\u00e2u khi xe \u00f4 t\u00f4 kh\u1edfi h\u00e0nh hai xe g\u1eb7p nhau?<br\/><b> \u0110\u00e1p s\u1ed1: <\/b> _input_ (gi\u1edd)<\/span>","hint":"Hai xe g\u1eb7p nhau th\u00ec t\u1ed5ng qu\u00e3ng \u0111\u01b0\u1eddng c\u1ee7a hai xe l\u00e0 \u0111\u1ed9 d\u00e0i \u0111o\u1ea1n \u0111\u01b0\u1eddng $AB$<br\/>\u00c1p d\u1ee5ng c\u00f4ng th\u1ee9c li\u00ean h\u1ec7 gi\u1eefa qu\u00e3ng \u0111\u01b0\u1eddng, v\u1eadn t\u1ed1c v\u00e0 th\u1eddi gian.","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn<\/span><br\/>L\u1eadp b\u1ea3ng:<br\/><table><tr><th><\/th><th>Qu\u00e3ng \u0111\u01b0\u1eddng ($km$)<\/th><th>V\u1eadn t\u1ed1c $(km\/h)$<\/th><th>Th\u1eddi gian (gi\u1edd)<\/th><\/tr><tr><td>\u00d4 t\u00f4<\/td><td>$50x$<\/td><td>$50$<\/td><td>$x$<\/td><\/tr><tr><td>Xe m\u00e1y<\/td><td>$40(x-2)$<\/td><td>$40$<\/td><td>$x-2$<\/td><\/tr><\/table><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i<\/span><br\/>G\u1ecdi th\u1eddi gian \u00f4 t\u00f4 \u0111i \u0111\u01b0\u1ee3c \u0111\u1ebfn khi g\u1eb7p nhau l\u00e0 $x$ ($km$, $x > 2$)<br\/>Qu\u00e3ng \u0111\u01b0\u1eddng \u00f4 t\u00f4 \u0111i \u0111\u01b0\u1ee3c l\u00e0 $50x$ ($km$)<br\/>V\u00ec xe m\u00e1y kh\u1eddi h\u00e0nh sau \u00f4 t\u00f4 $2$ gi\u1edd n\u00ean th\u1eddi gian xe m\u00e1y \u0111i l\u00e0 $x-2$ (gi\u1edd)<br\/>Qu\u00e3ng \u0111\u01b0\u1eddng xe m\u00e1y \u0111i \u0111\u01b0\u1ee3c l\u00e0 $40(x-2)$ ($km$)<br\/>Hai xe g\u1eb7p nhau n\u00ean ta c\u00f3 ph\u01b0\u01a1ng tr\u00ecnh:<br\/>$50x+40(x-2)=190\\\\ \\Leftrightarrow 90x=270\\\\ \\Leftrightarrow x=3\\,\\,\\text{(th\u1ecfa m\u00e3n)}$<br\/>V\u1eady sau $3$ gi\u1edd hai xe g\u1eb7p nhau.<br\/><span class='basic_pink'>V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $3$<\/span><\/span>"}]}],"id_ques":1008},{"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":[[["6"]]],"list":[{"point":5,"width":50,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai22/lv1/img\/12.jpg' \/><\/center><span class='basic_left'>Hai c\u00f4ng nh\u00e2n c\u00f9ng l\u00e0m m\u1ed9t c\u00f4ng vi\u1ec7c th\u00ec $2$ gi\u1edd th\u00ec xong. N\u1ebfu ng\u01b0\u1eddi th\u1ee9 nh\u1ea5t l\u00e0m m\u1ed9t m\u00ecnh trong $2$ gi\u1edd r\u1ed3i ng\u01b0\u1eddi th\u1ee9 hai l\u00e0m ti\u1ebfp trong $1$ gi\u1edd th\u00ec \u0111\u01b0\u1ee3c $\\dfrac {2}{3}$ c\u00f4ng vi\u1ec7c. T\u00ednh th\u1eddi gian ng\u01b0\u1eddi th\u1ee9 nh\u1ea5t l\u00e0m m\u1ed9t m\u00ecnh xong c\u00f4ng vi\u1ec7c.<br\/><b> \u0110\u00e1p s\u1ed1: <\/b> _input_ (gi\u1edd)<\/span>","hint":"","explain":"<span class='basic_left'>G\u1ecdi th\u1eddi gian ng\u01b0\u1eddi th\u1ee9 nh\u1ea5t l\u00e0m m\u1ed9t m\u00ecnh xong c\u00f4ng vi\u1ec7c l\u00e0 $x$ (gi\u1edd, $x>2$)<br\/>$1$ gi\u1edd ng\u01b0\u1eddi th\u1ee9 nh\u1ea5t l\u00e0m \u0111\u01b0\u1ee3c l\u00e0 $\\dfrac {1}{x} $ (c\u00f4ng vi\u1ec7c)<br\/>Trong $2$ gi\u1edd ng\u01b0\u1eddi th\u1ee9 nh\u1ea5t l\u00e0m \u0111\u01b0\u1ee3c l\u00e0 $\\dfrac {2}{x}$ (c\u00f4ng vi\u1ec7c)<br\/>V\u00ec hai ng\u01b0\u1eddi c\u00f9ng l\u00e0m trong $2$ gi\u1edd m\u1eddi ho\u00e0n th\u00e0nh c\u00f4ng vi\u1ec7c n\u00ean $1$ gi\u1edd c\u1ea3 hai ng\u01b0\u1eddi l\u00e0m \u0111\u01b0\u1ee3c l\u00e0 $\\dfrac {1}{2}$ (c\u00f4ng vi\u1ec7c)<br\/>V\u00ec $1$ gi\u1edd ng\u01b0\u1eddi th\u1ee9 nh\u1ea5t l\u00e0m \u0111\u01b0\u1ee3c $\\dfrac{1}{x}$ c\u00f4ng vi\u1ec7c n\u00ean $1$ gi\u1edd ng\u01b0\u1eddi th\u1ee9 hai l\u00e0m \u0111\u01b0\u1ee3c l\u00e0 $\\dfrac {1}{2}-\\dfrac{1}{x}$ (c\u00f4ng vi\u1ec7c)<br\/>V\u00ec khi \u0111\u00f3 hai ng\u01b0\u1eddi l\u00e0m \u0111\u01b0\u1ee3c $\\dfrac {2}{3}$ c\u00f4ng vi\u1ec7c n\u00ean ta c\u00f3 ph\u01b0\u01a1ng tr\u00ecnh:<br\/>$\\dfrac {2}{x}+\\left(\\dfrac {1}{2}-\\dfrac{1}{x}\\right)=\\dfrac{2}{3}\\\\ \\Leftrightarrow \\dfrac {2}{x}+\\dfrac {1}{2}-\\dfrac {1}{x}=\\dfrac {2}{3}\\\\ \\Leftrightarrow \\dfrac {1}{x}=\\dfrac {1}{6}\\\\ \\Leftrightarrow x=6\\,\\,\\text{(th\u1ecfa m\u00e3n)}$<br\/>V\u1eady ng\u01b0\u1eddi th\u1ee9 nh\u1ea5t l\u00e0m m\u1ed9t m\u00ecnh trong $6$ gi\u1edd th\u00ec ho\u00e0n th\u00e0nh c\u00f4ng vi\u1ec7c<br\/><span class='basic_pink'>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o ch\u1ed7 tr\u1ed1ng l\u00e0 $6$<\/span><\/span>"}]}],"id_ques":1009},{"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":[[["320"]]],"list":[{"point":5,"width":50,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai22/lv1/img\/15.jpg' \/><\/center><span class='basic_left'>M\u1ed9t ng\u01b0\u1eddi \u0111\u01b0\u1ee3c giao m\u1ed9t s\u1ed1 s\u1ea3n ph\u1ea9m, d\u1ef1 \u0111\u1ecbnh ph\u1ea3i l\u00e0m trong $20$ ng\u00e0y. V\u00ec m\u1ed7i ng\u00e0y ng\u01b0\u1eddi \u0111\u00f3 l\u00e0m nhi\u1ec1u h\u01a1n $2$ s\u1ea3n ph\u1ea9m n\u00ean kh\u00f4ng nh\u1eefng ho\u00e0n th\u00e0nh tr\u01b0\u1edbc $2$ ng\u00e0y m\u00e0 c\u00f2n l\u00e0m th\u00eam \u0111\u01b0\u1ee3c s\u1ea3n ph\u1ea9m $4$ s\u1ea3n ph\u1ea9m. T\u00ednh s\u1ed1 s\u1ea3n ph\u1ea9m \u0111\u01b0\u1ee3c giao.<br\/><b> \u0110\u00e1p s\u1ed1: <\/b> _input_ (s\u1ea3n ph\u1ea9m)<\/span>","hint":"\u0110\u00e2y l\u00e0 d\u1ea1ng to\u00e1n n\u0103ng su\u1ea5t: T\u1ed5ng s\u1ea3n ph\u1ea9m $=$ N\u0103ng su\u1ea5t $*$ Th\u1eddi gian ho\u00e0n th\u00e0nh.","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn<\/span><br\/>L\u1eadp b\u1ea3ng: <br\/><table><tr><th><\/th><th>T\u1ed5ng s\u1ea3n ph\u1ea9m<\/th><th>N\u0103ng su\u1ea5t<\/th><th>Th\u1eddi gian<\/th><\/tr><tr><td>D\u1ef1 \u0111\u1ecbnh<\/td><td>$x$<\/td><td>$\\dfrac{x}{20}$<\/td><td>$20$<\/td><\/tr><tr><td>Th\u1ef1c t\u1ebf<\/td><td>$x+4$<\/td><td>$\\dfrac{x+4}{18}$<\/td><td>$18$<\/td><\/tr><\/table><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i<\/span><br\/>G\u1ecdi s\u1ed1 s\u1ea3n ph\u1ea9m \u0111\u01b0\u1ee3c giao l\u00e0 $x$ (s\u1ea3n ph\u1ea9m, $x\\in\\mathbb N^*$)<br\/>N\u0103ng su\u1ea5t d\u1ef1 \u0111\u1ecbnh c\u1ee7a ng\u01b0\u1eddi \u0111\u00f3 l\u00e0 $\\dfrac {x}{20}$ (s\u1ea3n ph\u1ea9m\/ ng\u00e0y)<br\/>V\u00ec ng\u01b0\u1eddi \u0111\u00f3 l\u00e0m nhi\u1ec1u h\u01a1n s\u1ed1 s\u1ea3n ph\u1ea9m \u0111\u01b0\u1ee3c giao l\u00e0 $4$ s\u1ea3n ph\u1ea9m n\u00ean s\u1ed1 s\u1ea3n ph\u1ea9m th\u1ef1c t\u1ebf l\u00e0 $x+4$ (s\u1ea3n ph\u1ea9m)<br\/>V\u00ec ng\u01b0\u1eddi \u0111\u00f3 ho\u00e0n th\u00e0nh s\u1edbm h\u01a1n d\u1ef1 \u0111\u1ecbnh $2$ ng\u00e0y n\u00ean n\u0103ng su\u1ea5t th\u1ef1c t\u1ebf ng\u01b0\u1eddi \u0111\u00f3 l\u00e0m \u0111\u01b0\u1ee3c l\u00e0 $\\dfrac {x+4}{18}$(s\u1ea3n ph\u1ea9m\/ng\u00e0y)<br\/>V\u00ec m\u1ed7i ng\u00e0y l\u00e0m th\u00eam \u0111\u01b0\u1ee3c $2$ s\u1ea3n ph\u1ea9m n\u00ean ta c\u00f3 ph\u01b0\u01a1ng tr\u00ecnh: <br\/>$\\dfrac {x+4}{18}-\\dfrac {x}{20}=2\\\\ \\Leftrightarrow 10(x+4)-9x=360\\\\ \\Leftrightarrow x=320 \\,\\,\\text{(th\u1ecfa m\u00e3n)}$<br\/>V\u1eady ng\u01b0\u1eddi \u0111\u00f3 ph\u1ea3i l\u00e0m $320$ s\u1ea3n ph\u1ea9m.<br\/><span class='basic_pink'>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o ch\u1ed7 tr\u1ed1ng l\u00e0 $320$<\/span><\/span>"}]}],"id_ques":1010}],"lesson":{"save":0,"level":1}}