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{"segment":[{"time":24,"part":[{"time":3,"title":"N\u1ed1i c\u00e1c \u00fd \u1edf c\u1ed9t b\u00ean tr\u00e1i v\u1edbi c\u1ed9t b\u00ean ph\u1ea3i \u0111\u1ec3 \u0111\u01b0\u1ee3c c\u00e2u ho\u00e0n ch\u1ec9nh","title_trans":"N\u1ed1i c\u00e1c \u00fd \u1edf c\u1ed9t b\u00ean tr\u00e1i v\u1edbi c\u1ed9t b\u00ean ph\u1ea3i \u0111\u1ec3 \u0111\u01b0\u1ee3c c\u00e2u ho\u00e0n ch\u1ec9nh","audio":"","temp":"matching","correct":[["1","2","3"]],"list":[{"point":5,"image":"https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai2/lv1/img\/1.png","left":["$(x-2)(x-3)=0$","$(-x)(-x+5)=0$","$-(x+7)(x+1)=0$"],"right":["$x = 2$ ho\u1eb7c $x = 3$","$x = 0$ ho\u1eb7c $x = 5$","$x = -7$ ho\u1eb7c $x = - 1$"],"top":100,"hint":"Ta \u0111i t\u00ecm $x$ c\u1ee7a t\u1eebng tr\u01b0\u1eddng h\u1ee3p.<br\/> N\u1ebfu $a.b = 0 $ th\u00ec ho\u1eb7c $a = 0$ ho\u1eb7c $b = 0$.","explain":"+ Ta c\u00f3: $\\left( x-2 \\right)\\left( x-3 \\right)=0$<br\/>$\\Leftrightarrow \\left[ \\begin{aligned} & x-2=0 \\\\ & x-3=0 \\\\ \\end{aligned} \\right.\\Leftrightarrow \\left[ \\begin{aligned} & x=2 \\\\ & x=3 \\\\ \\end{aligned} \\right.$<br\/>+ Ta c\u00f3: $\\left( -x \\right)\\left( -5+x \\right)=0 $<br\/>$ \\Leftrightarrow \\left[ \\begin{aligned} & -x=0 \\\\ & -5+x=0\\\\ \\end{aligned} \\right.\\Leftrightarrow \\left[ \\begin{aligned} & x=0 \\\\ & x=5 \\\\ \\end{aligned} \\right.$<br\/>+ Ta c\u00f3: $-\\left( x+7 \\right)\\left( x+1 \\right)=0 $<br\/>$\\Leftrightarrow \\left[ \\begin{aligned} & x+7=0 \\\\ & x+1=0 \\\\ \\end{aligned} \\right.\\Leftrightarrow \\left[ \\begin{aligned} & x=-7 \\\\ & x=-1 \\\\ \\end{aligned} \\right.$ <br\/> <span class='basic_pink'>K\u1ebft lu\u1eadn:<br\/> N\u1ed1i $1$ v\u1edbi $x = 2$ ho\u1eb7c $x = 3$<br\/> N\u1ed1i $2$ v\u1edbi $x = 0$ ho\u1eb7c $x = 5$<br\/> N\u1ed1i $3$ v\u1edbi $x = -7$ ho\u1eb7c $x = - 1$.<\/span>"}]}],"id_ques":331},{"time":24,"part":[{"time":3,"title":"N\u1ed1i c\u00e1c \u00fd \u1edf c\u1ed9t b\u00ean tr\u00e1i v\u1edbi c\u1ed9t b\u00ean ph\u1ea3i \u0111\u1ec3 \u0111\u01b0\u1ee3c c\u00e2u ho\u00e0n ch\u1ec9nh","title_trans":"N\u1ed1i c\u00e1c \u00fd \u1edf c\u1ed9t b\u00ean tr\u00e1i v\u1edbi c\u1ed9t b\u00ean ph\u1ea3i \u0111\u1ec3 \u0111\u01b0\u1ee3c c\u00e2u ho\u00e0n ch\u1ec9nh","audio":"","temp":"matching","correct":[["3","1","2"]],"list":[{"point":10,"left":["$(x+5)(3x-9)$","$(x+12)(-5-x^4)$","$x(x+1)(x+2)$"],"right":["\u0110a th\u1ee9c b\u1eadc 5","\u0110a th\u1ee9c b\u1eadc 3","\u0110a th\u1ee9c b\u1eadc 2"],"top":100,"hint":"Ta th\u1ef1c hi\u1ec7n nh\u00e2n \u0111a th\u1ee9c v\u1edbi \u0111a th\u1ee9c $(a+b)(c+d)=ac+ad+bc+bd$<br\/>T\u00ecm l\u0169y th\u1eeba cao nh\u1ea5t c\u1ee7a bi\u1ebfn trong \u0111a th\u1ee9c thu \u0111\u01b0\u1ee3c, \u0111\u00f3 ch\u00ednh l\u00e0 b\u1eadc c\u1ee7a \u0111a th\u1ee9c m\u1ed9t bi\u1ebfn. ","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/><b>B\u01b0\u1edbc 1:<\/b> Ta th\u1ef1c hi\u1ec7n nh\u00e2n \u0111a th\u1ee9c v\u1edbi \u0111a th\u1ee9c $(a+b)(c+d)=ac+ad+bc+bd$<br\/> <b>B\u01b0\u1edbc 2:<\/b> T\u00ecm l\u0169y th\u1eeba cao nh\u1ea5t c\u1ee7a bi\u1ebfn trong \u0111a th\u1ee9c thu \u0111\u01b0\u1ee3c, \u0111\u00f3 ch\u00ednh l\u00e0 b\u1eadc c\u1ee7a \u0111a th\u1ee9c m\u1ed9t bi\u1ebfn.<br\/> <b>B\u01b0\u1edbc 3:<\/b> N\u1ed1i hai c\u1ed9t theo y\u00eau c\u1ea7u. <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta th\u1ef1c hi\u1ec7n nh\u00e2n \u0111a th\u1ee9c v\u1edbi \u0111a th\u1ee9c \u1edf t\u1eebng ph\u00e9p t\u00ednh \u1edf c\u1ed9t v\u1ebf tr\u00e1i:<br\/>$\\left( x+5 \\right)\\left( 3x-9 \\right)$$=3{{x}^{2}}-9x+15x-45$$=3{{x}^{2}}+6x-45$<br\/>K\u1ebft qu\u1ea3 l\u00e0 \u0111a th\u1ee9c c\u00f3 l\u0169y th\u1eeba l\u1edbn nh\u1ea5t c\u1ee7a x l\u00e0 2 n\u00ean \u0111a th\u1ee9c thu \u0111\u01b0\u1ee3c l\u00e0 \u0111a th\u1ee9c b\u1eadc 2. <br\/> $\\left( x+12 \\right)\\left( -5-x^4 \\right)$$=-5x-x^5-60-12x^4$$=-x^5-12x^4-5x-60$ <br\/>K\u1ebft qu\u1ea3 l\u00e0 \u0111a th\u1ee9c c\u00f3 l\u0169y th\u1eeba l\u1edbn nh\u1ea5t c\u1ee7a x l\u00e0 5 n\u00ean \u0111a th\u1ee9c thu \u0111\u01b0\u1ee3c l\u00e0 \u0111a th\u1ee9c b\u1eadc 5. <br\/>$x(x+1)(x+2)=(x^2+x)(x+2)$$=x^3+2x^2+x^2+2x=x^3+3x^2+2x$<br\/>K\u1ebft qu\u1ea3 l\u00e0 \u0111a th\u1ee9c c\u00f3 l\u0169y th\u1eeba l\u1edbn nh\u1ea5t c\u1ee7a x l\u00e0 3 n\u00ean \u0111a th\u1ee9c thu \u0111\u01b0\u1ee3c l\u00e0 \u0111a th\u1ee9c b\u1eadc 3. <br\/> <span class='basic_pink'>K\u1ebft lu\u1eadn: <br\/> N\u1ed1i 1 v\u1edbi \u0111a th\u1ee9c b\u1eadc 2<br\/> N\u1ed1i 2 v\u1edbi \u0111a th\u1ee9c b\u1eadc 5<br\/> N\u1ed1i 3 v\u1edbi \u0111a th\u1ee9c b\u1eadc 3.<\/span><\/span><\/span> "}]}],"id_ques":332},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai2/lv1/img\/1.png' \/><\/center>Bi\u1ec3u th\u1ee9c $\\left( \\dfrac{1}{2}{{x}^{4}}+3 \\right)\\left( -1+{{x}^{3}} \\right)$ l\u00e0 \u0111a th\u1ee9c b\u1eadc $7$ <b> \u0111\u00fang <\/b> hay <b> sai? <\/b>","select":["\u0110\u00fang","Sai"],"hint":"<br\/>Ta nh\u00e2n \u0111a th\u1ee9c v\u1edbi \u0111a th\u1ee9c, s\u1eed d\u1ee5ng c\u00f4ng th\u1ee9c: $(a+b)(c+d)=ac+ad+bc+bd$<br\/> B\u1eadc c\u1ee7a \u0111a th\u1ee9c m\u1ed9t bi\u1ebfn l\u00e0 l\u0169y th\u1eeba cao nh\u1ea5t c\u1ee7a bi\u1ebfn trong \u0111a th\u1ee9c","explain":"<span class='basic_green'>Gi\u1ea3i<\/span><br\/><span class='basic_left'>Ta th\u1ef1c hi\u1ec7n ph\u00e9p nh\u00e2n:<br\/>$\\left( \\dfrac{1}{2}{{x}^{4}}+3 \\right)\\left( -1+{{x}^{3}} \\right)$$=-\\dfrac{1}{2}{{x}^{4}}+\\dfrac{1}{2}{{x}^{7}}-3+3{{x}^{3}}$$=\\dfrac{1}{2}{{x}^{7}}-\\dfrac{1}{2}{{x}^{4}}+3{{x}^{3}}-3$<br\/>\u0110a th\u1ee9c thu \u0111\u01b0\u1ee3c c\u00f3 b\u1eadc l\u00e0 $7$<span><br\/> <span class='basic_pink'> V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0110\u00fang.<\/span>","column":2}]}],"id_ques":333},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai2/lv1/img\/1.png' \/><\/center>Bi\u1ec3u th\u1ee9c $\\left( {{x}^{3}}-1 \\right)\\left( 1+5{{x}^{3}} \\right)$ l\u00e0 \u0111a th\u1ee9c b\u1eadc 9 <b> \u0111\u00fang <\/b> hay <b> sai? <\/b> ","select":["\u0110\u00fang","Sai"],"hint":"<br\/>Ta nh\u00e2n \u0111a th\u1ee9c v\u1edbi \u0111a th\u1ee9c, s\u1eed d\u1ee5ng c\u00f4ng th\u1ee9c: $(a+b)(c+d)=ac+ad+bc+bd$<br\/> Sau \u0111\u00f3 nh\u1eadn \u0111\u1ecbnh b\u1eadc c\u1ee7a \u0111a th\u1ee9c thu \u0111\u01b0\u1ee3c.","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn<\/span><br\/> <b>B\u01b0\u1edbc 1:<\/b> Ta nh\u00e2n \u0111a th\u1ee9c v\u1edbi \u0111a th\u1ee9c, s\u1eed d\u1ee5ng c\u00f4ng th\u1ee9c: $(a+b)(c+d)=ac+ad+bc+bd$ <br\/> <b>B\u01b0\u1edbc 2:<\/b> S\u1eafp x\u1ebfp k\u1ebft qu\u1ea3 theo l\u0169y th\u1eeba gi\u1ea3m d\u1ea7n v\u00e0 sau \u0111\u00f3 nh\u1eadn \u0111\u1ecbnh b\u1eadc c\u1ee7a \u0111a th\u1ee9c thu \u0111\u01b0\u1ee3c.<br\/><span class='basic_green'>Gi\u1ea3i<\/span><br\/><span class='basic_left'>Ta th\u1ef1c hi\u1ec7n ph\u00e9p nh\u00e2n:<br\/>$\\left( {{x}^{3}}-1 \\right)\\left( 1+5{{x}^{3}} \\right)$$={{x}^{3}}+5{{x}^{6}}-1-5{{x}^{3}}$$=5{{x}^{6}}-4{{x}^{3}}-1$<br\/>\u0110a th\u1ee9c thu \u0111\u01b0\u1ee3c c\u00f3 b\u1eadc l\u00e0 6<span><br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0: Sai.<\/span>","column":2}]}],"id_ques":334},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 \u0111\u00fang nh\u1ea5t v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank_random","correct":[[["-16"],["4"]]],"list":[{"point":5,"width":40,"content":"","type_input":"","ques":"T\u00ecm $b$, bi\u1ebft: $\\left( 2b+32 \\right)\\left( 2b-8 \\right)=0 $ . <br\/> Gi\u00e1 tr\u1ecb c\u1ee7a $b$ c\u1ea7n t\u00ecm l\u00e0 $\\left[ \\begin{aligned}& b=\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{} \\\\ & b=\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{} \\\\ \\end{aligned} \\right.$","hint":"N\u1ebfu $a.b = 0$ th\u00ec $a = 0$ ho\u1eb7c $b = 0$.","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$ \\left( 2b+32 \\right)\\left( 2b-8 \\right)=0 $$ \\Leftrightarrow \\left[ \\begin{aligned}& 2b+32=0 \\\\ & 2b-8=0 \\\\ \\end{aligned} \\right.\\Leftrightarrow \\left[ \\begin{aligned}& 2b=-32 \\\\ & 2b=8 \\\\ \\end{aligned} \\right.\\Leftrightarrow \\left[ \\begin{aligned}& b=-16 \\\\ & b=4 \\\\ \\end{aligned} \\right. $<br\/> <span class='basic_pink'> V\u1eady gi\u00e1 tr\u1ecb $b$ c\u1ea7n \u0111i\u1ec1n l\u00e0 $-16$ ho\u1eb7c $4$.<\/span>"}]}],"id_ques":335},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 \u0111\u00fang nh\u1ea5t v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank_random","correct":[[["-1"],["-6"]]],"list":[{"point":5,"width":40,"content":"","type_input":"","ques":"T\u00ecm $x$, bi\u1ebft: $-\\left( -x-6 \\right)\\left( -\\dfrac{1}{3}x-\\dfrac{1}{3} \\right)=0$. <br\/> Gi\u00e1 tr\u1ecb c\u1ee7a $x$ c\u1ea7n t\u00ecm l\u00e0 _input_ ho\u1eb7c _input_","hint":"N\u1ebfu $a.b = 0$ th\u00ec $a = 0$ ho\u1eb7c $b = 0.$","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$ -\\left( -x-6 \\right)\\left( -\\dfrac{1}{3}x-\\dfrac{1}{3} \\right)=0 $<br\/>$ \\Rightarrow \\left[ \\begin{aligned}& -x-6=0 \\\\ & -\\dfrac{1}{3}x-\\dfrac{1}{3}=0 \\\\ \\end{aligned} \\right.$$\\Leftrightarrow \\left[ \\begin{aligned}& x=-6 \\\\ & -\\dfrac{1}{3}x=\\dfrac{1}{3} \\\\ \\end{aligned} \\right.$$\\Leftrightarrow \\left[ \\begin{aligned}& x=-6 \\\\ & x=-1 \\\\ \\end{aligned} \\right. $<br\/> <span class='basic_pink'> V\u1eady gi\u00e1 tr\u1ecb $x$ c\u1ea7n \u0111i\u1ec1n l\u00e0 $-1$ ho\u1eb7c $-6$.<\/span>"}]}],"id_ques":336},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 \u0111\u00fang nh\u1ea5t v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank_random","correct":[[["1"],["-2"]]],"list":[{"point":5,"width":40,"content":"","type_input":"","ques":"T\u00ecm $a$, bi\u1ebft: $\\left( 2a+4 \\right)\\left( -\\dfrac{1}{2}a+\\dfrac{1}{2} \\right)=0$. <br\/> Gi\u00e1 tr\u1ecb c\u1ee7a $a$ c\u1ea7n t\u00ecm l\u00e0 _input_ ho\u1eb7c _input_","hint":"N\u1ebfu $a.b = 0$ th\u00ec $a = 0$ ho\u1eb7c $b = 0.$","explain":"<span class='basic_left'>Ta c\u00f3:<br\/>$\\left( 2a+4 \\right)\\left( -\\dfrac{1}{2}a+\\dfrac{1}{2} \\right)=0$$\\Rightarrow \\left[\\begin{aligned}& 2a+4=0 \\\\ & -\\dfrac{1}{2}a+\\dfrac{1}{2}=0 \\\\ \\end{aligned} \\right.$$\\Leftrightarrow \\left[ \\begin{aligned}& 2a=-4 \\\\ & -\\dfrac{1}{2}a=-\\dfrac{1}{2} \\\\ \\end{aligned} \\right.\\Leftrightarrow \\left[ \\begin{aligned}& a=-2 \\\\ & a=1 \\\\ \\end{aligned} \\right.$<br\/> <span class='basic_pink'> V\u1eady gi\u00e1 tr\u1ecb $a$ c\u1ea7n \u0111i\u1ec1n l\u00e0 $1$ ho\u1eb7c $-2$.<\/span>"}]}],"id_ques":337},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 \u0111\u00fang nh\u1ea5t v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["3"]]],"list":[{"point":5,"width":40,"type_input":"","ques":"Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c $-\\left( \\dfrac{1}{2}b-2 \\right)\\left( b+1 \\right)$ t\u1ea1i $b = 2$ l\u00e0 _input_","hint":"Thay gi\u00e1 tr\u1ecb c\u1ee7a $b$ v\u00e0o bi\u1ec3u th\u1ee9c \u0111\u00e3 cho v\u00e0 t\u00ednh.","explain":"<span class='basic_left'>Thay $b = 2$ v\u00e0o bi\u1ec3u th\u1ee9c $-\\left( \\dfrac{1}{2}b-2 \\right)\\left( b+1 \\right)$, ta \u0111\u01b0\u1ee3c:<br\/> $-\\left( \\dfrac{1}{2}.2-2 \\right)\\left( 2+1 \\right)=3$<br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $3$.<\/span><\/span>"}]}],"id_ques":338},{"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/bai2/lv1/img\/1.png' \/><\/center>Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c $\\left( x-3 \\right)(y+4)$ t\u1ea1i $x = 2; y = 0$ l\u00e0: ","select":["A. $-4$","B. $-6$","C. 0","D. 12"],"hint":"Thay gi\u00e1 tr\u1ecb c\u1ee7a $x$ v\u00e0 $y$ v\u00e0o bi\u1ec3u th\u1ee9c \u0111\u00e3 cho \u0111\u1ec3 t\u00ednh.","explain":"<span class='basic_left'> Thay $x = 2; y = 0$ v\u00e0o$\\left( x-3 \\right)(y+4)$, ta \u0111\u01b0\u1ee3c:<br\/> $\\left( 2-3 \\right)\\left( 0+4 \\right)=-4$<br\/><span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span><br\/> <\/span>","column":2}]}],"id_ques":339},{"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/bai2/lv1/img\/1.png' \/><\/center>Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c $\\left( {{x}^{2}}-3 \\right)\\left( y-3 \\right)$ b\u1eb1ng $0$ t\u1ea1i: ","select":["A. $x = 0; y = 3$","B. $x = 1 ; y = 0$","C. $x = y = 1$","D. $x = 3; y = 0$"],"hint":"Thay gi\u00e1 tr\u1ecb c\u1ee7a $x, y$ \u1edf c\u00e1c \u0111\u00e1p \u00e1n \u0111\u00e3 cho \u0111\u1ec3 t\u00ecm \u0111\u00e1p \u00e1n th\u1ecfa m\u00e3n \u0111\u1ec1 b\u00e0i","explain":"<span class='basic_left'>+ V\u1edbi $x = 0; y = 3$ th\u00ec $\\left( {{x}^{2}}-3 \\right)\\left( y-3 \\right)=(0-3)(3-3)=0$ (th\u1ecfa m\u00e3n)<br\/> + V\u1edbi $x = 1; y = 0$ th\u00ec $\\left( {{x}^{2}}-3 \\right)\\left( y-3 \\right)=(1-3)(0-3)=6$ (lo\u1ea1i).<br\/> + V\u1edbi $x = y = 1$ th\u00ec $\\left( {{x}^{2}}-3 \\right)\\left( y-3 \\right)=(1-3)(1-3)=4$ (lo\u1ea1i)<br\/> + V\u1edbi $x = 3; y = 0$ th\u00ec $\\left( {{x}^{2}}-3 \\right)\\left( y-3 \\right)$$=(3^2-3)(0-3)=-18$ (lo\u1ea1i)<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n l\u00e0 A.<\/span><\/span> <\/span> ","column":2}]}],"id_ques":340},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai2/lv1/img\/1.png' \/><\/center>Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c $\\left( 1-5x \\right)\\left( y+3 \\right)$ t\u1ea1i $x = 1; y = 2$ l\u00e0: ","select":["A. $-40$","B. $-20$","C. $-50$","D. $-30$"],"hint":"Thay gi\u00e1 tr\u1ecb c\u1ee7a x v\u00e0 y v\u00e0o bi\u1ec3u th\u1ee9c \u0111\u00e3 cho \u0111\u1ec3 t\u00ednh.","explain":"<span class='basic_left'> Thay $x = 1; y = 2$ v\u00e0o bi\u1ec3u th\u1ee9c $\\left( 1-5x \\right)\\left( y+3 \\right)$, ta \u0111\u01b0\u1ee3c:<br\/> $\\left( 1-5.1 \\right)\\left( 2+3 \\right)$$=\\left( -4 \\right).5=-20$<br\/><span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span><br\/> <\/span>","column":2}]}],"id_ques":341},{"time":24,"part":[{"title":"\u0110i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng ","title_trans":"","temp":"fill_the_blank","correct":[[["0"]]],"list":[{"point":5,"width":40,"type_input":"","ques":"Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c $\\left( y-1 \\right)\\left( {{x}^{2}}+1 \\right)$ t\u1ea1i $x = 1; y = 1$ l\u00e0 _input_","hint":"Thay gi\u00e1 tr\u1ecb $x, y$ v\u00e0o bi\u1ec3u th\u1ee9c \u0111\u1ec3 t\u00ednh","explain":"<span class='basic_left'>Ta thay $x = 1; y = 1$ v\u00e0o bi\u1ec3u th\u1ee9c $\\left( y-1 \\right)\\left( {{x}^{2}}+1 \\right)$ ta \u0111\u01b0\u1ee3c:<br\/> $(1-1)(1^2+1)=0$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n c\u1ea7n \u0111i\u1ec1n l\u00e0 $0$.<\/span> <\/span>"}]}],"id_ques":342},{"time":24,"part":[{"title":"\u0110i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng \u0111\u1ec3 \u0111\u01b0\u1ee3c khai tri\u1ec3n \u0111\u00fang","title_trans":"","temp":"fill_the_blank","correct":[[["c"]]],"list":[{"point":5,"width":40,"type_input":"","ques":"$\\left( -c+1 \\right)\\left( \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}+1 \\right)=-{{c}^{2}}+1$","hint":"Bi\u1ebfn \u0111\u1ed5i $VP$ l\u00e0m xu\u1ea5t hi\u1ec7n nh\u00e2n t\u1eed gi\u1ed1ng $VT$. V\u00ec $VT = VP$ $\\Rightarrow$ nh\u00e2n t\u1eed c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng","explain":"<span class='basic_left'> Ta c\u00f3: <br\/> $VP$ = $-{{c}^{2}}+1 = (-c + 1)(c + 1) $ <br\/> V\u00ec $VT = VP$ $\\Rightarrow$ $(-c + 1)(c + 1) = (-c + 1)(c + 1)$ <span><br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $c$.<\/span><\/span>"}]}],"id_ques":343},{"time":24,"part":[{"title":"\u0110i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng \u0111\u1ec3 \u0111\u01b0\u1ee3c khai tri\u1ec3n \u0111\u00fang","title_trans":"","temp":"fill_the_blank","correct":[[["3b"],["6"]]],"list":[{"point":5,"width":40,"type_input":"","ques":"$-\\left( b-2 \\right)\\left( b-3 \\right)$$=-{{b}^{2}}+\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}+2b-\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}\\,$","hint":"Nh\u00e2n \u0111a th\u1ee9c n\u00e0y v\u1edbi t\u1eebng h\u1ea1ng t\u1eed c\u1ee7a \u0111a th\u1ee9c kia: $(a+b)(c+d) = ac+ad+bc+bd$, t\u1eeb \u0111\u00f3 t\u00ecm ra y\u1ebfu t\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng.","explain":"<span class='basic_left'>Ta c\u00f3:<br\/> $-\\left( b-2 \\right)\\left( b-3 \\right)$$=-\\left( {{b}^{2}}-3b-2b+6 \\right)$$=-{{b}^{2}}+3b+2b-6$<span><br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $3b$ v\u00e0 $6$.<\/span>"}]}],"id_ques":344},{"time":24,"part":[{"title":"\u0110i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng \u0111\u1ec3 \u0111\u01b0\u1ee3c khai tri\u1ec3n \u0111\u00fang","title_trans":"","temp":"fill_the_blank","correct":[[["z"]]],"list":[{"point":5,"width":40,"type_input":"","ques":"$\\left( \\dfrac{1}{2}y+1 \\right)\\left(\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{} +1 \\right)$$=\\dfrac{1}{2}yz+\\dfrac{1}{2}y+z+1$","hint":"Bi\u1ebfn \u0111\u1ed5i $VP$ l\u00e0m xu\u1ea5t hi\u1ec7n h\u1ea1ng t\u1eed gi\u1ed1ng $VT$. V\u00ec $VT$ = $VP$ $\\Rightarrow$ h\u1ea1ng t\u1eed c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng","explain":"<span class='basic_left'>Ta c\u00f3: <br\/> $VP$ = $\\dfrac{1}{2}yz+\\dfrac{1}{2}y+z+1 = \\dfrac{1}{2}y (z + 1) + (z + 1) = \\left( \\dfrac{1}{2}y + 1 \\right) (z + 1)$ <br\/> V\u00ec $VT$ = $VP$ $\\Rightarrow$ $\\left( \\dfrac{1}{2}y + 1 \\right) ( .......... + 1) = \\left( \\dfrac{1}{2}y + 1 \\right) (z + 1)$ <span><br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $z$.<\/span>"}]}],"id_ques":345},{"time":24,"part":[{"title":"\u0110i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng \u0111\u1ec3 \u0111\u01b0\u1ee3c khai tri\u1ec3n \u0111\u00fang","title_trans":"","temp":"fill_the_blank_random","correct":[[["2x"],["2z"]]],"list":[{"point":5,"width":40,"type_input":"","ques":"$\\left( y-2 \\right)\\left( x+z \\right)$$=yx+yz-\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}-\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}$","hint":"Nh\u00e2n \u0111a th\u1ee9c n\u00e0y v\u1edbi t\u1eebng h\u1ea1ng t\u1eed c\u1ee7a \u0111a th\u1ee9c kia: $(a+b)(c+d) = ac+ad+bc+bd$, t\u1eeb \u0111\u00f3 t\u00ecm ra y\u1ebfu t\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng.","explain":"<span class='basic_left'>Ta th\u1ef1c hi\u1ec7n ph\u00e9p nh\u00e2n:<br\/> $\\left( y-2 \\right)\\left( x+z \\right)=xy+yz-2x-2z$<span><br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $2x$ v\u00e0 $2z$.<\/span>"}]}],"id_ques":346},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai2/lv1/img\/1.png' \/><\/center>K\u1ebft qu\u1ea3 ph\u00e9p nh\u00e2n $-\\left( 1-x \\right)\\left( 1-x \\right)$ l\u00e0:","select":["A. ${{x}^{2}}-2x+1$","B. ${{x}^{2}}-x+1$","C. $-{{x}^{2}}+2x-1$","D. ${{x}^{2}}+2x+1$"],"hint":"Nh\u00e2n \u0111a th\u1ee9c n\u00e0y v\u1edbi t\u1eebng h\u1ea1ng t\u1eed c\u1ee7a \u0111a th\u1ee9c kia: $(a+b)(c+d) = ac+ad+bc+bd$","explain":"<span class='basic_left'>Ta c\u00f3:<br\/> $-\\left( 1-x \\right)\\left( 1-x \\right)$$=-\\left( 1-x-x+{{x}^{2}} \\right)$$=-\\left( 1-2x+{{x}^{2}} \\right)$$=-{{x}^{2}}+2x-1$<span><br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span>","column":2}]}],"id_ques":347},{"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/bai2/lv1/img\/1.png' \/><\/center>K\u1ebft qu\u1ea3 ph\u00e9p nh\u00e2n $\\left( 2-y \\right)\\left( x+y \\right)$ l\u00e0:","select":["A. $2x+2y-xy-{{y}^{2}}$ ","B. $2x+2y+xy+{{y}^{2}}$ ","C. $-{{y}^{2}}+xy+2x$","D. $2x-x+y$"],"hint":"Nh\u00e2n \u0111a th\u1ee9c n\u00e0y v\u1edbi t\u1eebng h\u1ea1ng t\u1eed c\u1ee7a \u0111a th\u1ee9c kia: $(a+b)(c+d) = ac+ad+bc+bd$","explain":"<span class='basic_left'>Ta c\u00f3:<br\/> $\\left( 2-y \\right)\\left( x+y \\right)=2x+2y-xy-{{y}^{2}}$ <span><br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span>","column":2}]}],"id_ques":348},{"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/bai2/lv1/img\/1.png' \/><\/center>K\u1ebft qu\u1ea3 ph\u00e9p nh\u00e2n $\\left( b-2 \\right)\\left( b-2 \\right)$ l\u00e0:","select":["A. ${{b}^{2}}-4b+4$","B. ${{b}^{2}}+4b+4$","C. $b^2+4b$","D. $b^2-4$"],"hint":"Nh\u00e2n \u0111a th\u1ee9c n\u00e0y v\u1edbi t\u1eebng h\u1ea1ng t\u1eed c\u1ee7a \u0111a th\u1ee9c kia: $(a+b)(c+d) = ac+ad+bc+bd$","explain":"<span class='basic_left'>Ta c\u00f3: <br\/> $\\left( b-2 \\right)\\left( b-2 \\right)$$={{b}^{2}}-2b-2b+4={{b}^{2}}-4b+4$<span><br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span>","column":2}]}],"id_ques":349},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai2/lv1/img\/1.png' \/><\/center>K\u1ebft qu\u1ea3 ph\u00e9p nh\u00e2n $\\left( a+1 \\right)\\left( a-1 \\right)$ l\u00e0:","select":["A. ${{a}^{2}}-2a+1$","B. ${{a}^{2}}+2a+1$","C. $a^2+4a$","D. $a^2-1$"],"hint":"Nh\u00e2n \u0111a th\u1ee9c n\u00e0y v\u1edbi t\u1eebng h\u1ea1ng t\u1eed c\u1ee7a \u0111a th\u1ee9c kia: $(a+b)(c+d) = ac+ad+bc+bd$","explain":"<span class='basic_left'>Ta c\u00f3:<br\/> $\\left( a+1 \\right)\\left( a-1 \\right)$$={{a}^{2}}-a+a-1={{a}^{2}}-1$<span><br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span>","column":2}]}],"id_ques":350}],"lesson":{"save":0,"level":1}}

Điểm của bạn.

Câu hỏi này theo dạng chọn đáp án đúng, sau khi đọc xong câu hỏi, bạn bấm vào một trong số các đáp án mà chương trình đưa ra bên dưới, sau đó bấm vào nút gửi để kiểm tra đáp án và sẵn sàng chuyển sang câu hỏi kế tiếp

Trả lời đúng trong khoảng thời gian quy định bạn sẽ được + số điểm như sau:
Trong khoảng 1 phút đầu tiên + 5 điểm
Trong khoảng 1 phút -> 2 phút + 4 điểm
Trong khoảng 2 phút -> 3 phút + 3 điểm
Trong khoảng 3 phút -> 4 phút + 2 điểm
Trong khoảng 4 phút -> 5 phút + 1 điểm

Quá 5 phút: không được cộng điểm

Tổng thời gian làm mỗi câu (không giới hạn)

Điểm của bạn.

Bấm vào đây nếu phát hiện có lỗi hoặc muốn gửi góp ý