{"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}}