{"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":[["3","2","1"]],"list":[{"point":5,"image":"https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/1.png","left":["$(m-n^2)(m^2+mn^2+n^4)$","$(m+n^2)(m^2-mn^2+n^4)$","$m^3-3m^2n+3mn^2-n^3$"],"right":["$(m-n)^3$","$m^3+n^6$","$m^3-n^6$"],"top":100,"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>Ta r\u00fat g\u1ecdn c\u00e1c c\u00e2u \u1edf c\u1ed9t tr\u00e1i theo h\u1eb1ng \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 h\u1ecdc. T\u1eeb \u0111\u00f3 so s\u00e1nh c\u00e1c \u0111\u00e1p \u00e1n b\u00ean c\u1ed9t ph\u1ea3i \u0111\u1ec3 n\u1ed1i.<br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3: <br\/>$(m-n^2)(m^2+mn^2+n^4)=m^3-(n^2)^3$$=m^3-n^6$<br\/> $(m+n^2)(m^2-mn^2+n^4)$$=m^3+(n^2)^3=m^3+n^6$<br\/>$m^3-3m^2n+3mn^2-n^3$$=(m-n)^3$ <br\/> <span class='basic_pink'>K\u1ebft lu\u1eadn:<br\/> N\u1ed1i $1$ v\u1edbi $m^3-n^6$<br\/> N\u1ed1i $2$ v\u1edbi $m^3+n^6$<br\/> N\u1ed1i $3$ v\u1edbi $(m-n)^3$<\/span> <\/span>"}]}],"id_ques":501},{"time":24,"part":[{"time":3,"title":"N\u1ed1i c\u00e1c \u00fd \u1edf c\u1ed9t b\u00ean tr\u00e1i v\u1edbi c\u1ed9t b\u00ean ph\u1ea3i \u0111\u1ec3 \u0111\u01b0\u1ee3c c\u00e2u ho\u00e0n ch\u1ec9nh","title_trans":"N\u1ed1i c\u00e1c \u00fd \u1edf c\u1ed9t b\u00ean tr\u00e1i v\u1edbi c\u1ed9t b\u00ean ph\u1ea3i \u0111\u1ec3 \u0111\u01b0\u1ee3c c\u00e2u ho\u00e0n ch\u1ec9nh","audio":"","temp":"matching","correct":[["2","3","1"]],"list":[{"point":5,"image":"https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/2.jpg","left":["$64x^3-125$","$8x^3+y^3$","$(2x+y)^3$"],"right":["$8x^3+12x^2y+6xy^2+y^3$","$(4x-5)(16x^2+20x+25)$","$(2x+y)(4x^2-2xy+y^2)$"],"top":100,"hint":"Ta khai tri\u1ec3n c\u00e1c c\u00e2u \u1edf c\u1ed9t tr\u00e1i theo h\u1eb1ng \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 h\u1ecdc. T\u1eeb \u0111\u00f3 so s\u00e1nh c\u00e1c \u0111\u00e1p \u00e1n b\u00ean c\u1ed9t ph\u1ea3i \u0111\u1ec3 n\u1ed1i.","explain":"<span class='basic_left'>Ta c\u00f3: <br\/>$64x^3-125$$=(4x-5)(16x^2+20x+25)$<br\/> $8x^3+y^3$$=(2x+y)(4x^2-2xy+y^2)$<br\/> $(2x+y)^3$$=8x^3+12x^2y+6xy^2+y^3$ <br\/> <span class='basic_pink'>K\u1ebft lu\u1eadn:<br\/> N\u1ed1i $1$ v\u1edbi $(4x-5)(16x^2+20x+25)$<br\/> N\u1ed1i $2$ v\u1edbi $(2x+y)(4x^2-2xy+y^2)$<br\/> N\u1ed1i $3$ v\u1edbi $8x^3+12x^2y+6xy^2+y^3$<\/span> <\/span>"}]}],"id_ques":502},{"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/bai5/lv2/img\/4.jpg' \/><\/center> Ta lu\u00f4n c\u00f3: $(10a^2-1)(100a^4+10a^2+1)$$=1000a^6-1$, <b> \u0111\u00fang <\/b> hay <b> sai <\/b>? ","select":["\u0110\u00fang","Sai"],"hint":" S\u1eed d\u1ee5ng c\u00e1c h\u1eb1ng \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 h\u1ecdc \u0111\u1ec3 r\u00fat g\u1ecdn bi\u1ec3u th\u1ee9c v\u1ebf tr\u00e1i.<br\/> N\u1ebfu k\u1ebft qu\u1ea3 r\u00fat g\u1ecdn b\u1eb1ng v\u1edbi v\u1ebf ph\u1ea3i th\u00ec kh\u1eb3ng \u0111\u1ecbnh tr\u00ean l\u00e0 \u0111\u00fang v\u00e0 ng\u01b0\u1ee3c l\u1ea1i. ","explain":"<span class='basic_left'> Ta c\u00f3:<br\/>V\u1ebf tr\u00e1i $=(10a^2-1)(100a^4+10a^2+1)$$=(10a^2)^3-1^3=1000a^6-1=$ v\u1ebf ph\u1ea3i. <br\/> Kh\u1eb3ng \u0111\u1ecbnh tr\u00ean l\u00e0 \u0111\u00fang.<br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 \u0110\u00fang.<\/span>","column":2}]}],"id_ques":503},{"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/bai5/lv2/img\/4.jpg' \/><\/center>Bi\u1ec3u th\u1ee9c $A=(x-1)(x^2+x+1)$$-(x+1)(x^2-x+1)-x$ <br\/> kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o gi\u00e1 tr\u1ecb c\u1ee7a $x$, <b> \u0111\u00fang <\/b> hay <b> sai <\/b>? ","select":["\u0110\u00fang","Sai"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn<\/span><br\/> S\u1eed d\u1ee5ng c\u00e1c h\u1eb1ng \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 h\u1ecdc \u0111\u1ec3 r\u00fat g\u1ecdn bi\u1ec3u th\u1ee9c $A$.<br\/> N\u1ebfu k\u1ebft qu\u1ea3 r\u00fat g\u1ecdn bi\u1ec3u th\u1ee9c $A$ kh\u00f4ng ch\u1ee9a $x$ th\u00ec gi\u00e1 tr\u1ecb c\u1ee7a $A$ kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o bi\u1ebfn $x$ v\u00e0 ng\u01b0\u1ee3c l\u1ea1i.<br\/> <span class='basic_green'>Gi\u1ea3i<\/span><br\/><span class='basic_left'> Ta c\u00f3: <br\/> $ A=(x-1)({{x}^{2}}+x+1)$$-(x+1)({{x}^{2}}-x+1)-x $<br\/>$ ={{x}^{3}}-1-\\left( {{x}^{3}}+1 \\right)-x $<br\/>$ ={{x}^{3}}-1-{{x}^{3}}-1-x $<br\/>$ =-x - 2 $ <br\/> Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c $A$ ph\u1ee5 thu\u1ed9c v\u00e0o $x$. <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 Sai.<\/span>","column":2}]}],"id_ques":504},{"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/bai5/lv2/img\/5.jpg' \/><\/center>Bi\u1ec3u th\u1ee9c $A=(x+2)^3-(x-2)^3-12x^2$ kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o gi\u00e1 tr\u1ecb c\u1ee7a $x$, <b> \u0111\u00fang <\/b> hay <b> sai <\/b>? ","select":["\u0110\u00fang","Sai"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn<\/span><br\/> S\u1eed d\u1ee5ng c\u00e1c h\u1eb1ng \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 h\u1ecdc \u0111\u1ec3 r\u00fat g\u1ecdn bi\u1ec3u th\u1ee9c $A$.<br\/> N\u1ebfu k\u1ebft qu\u1ea3 r\u00fat g\u1ecdn bi\u1ec3u th\u1ee9c $A$ kh\u00f4ng ch\u1ee9a $x$ th\u00ec gi\u00e1 tr\u1ecb c\u1ee7a $A$ kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o bi\u1ebfn $x$ v\u00e0 ng\u01b0\u1ee3c l\u1ea1i.<br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i<\/span><br\/><span class='basic_left'> Ta c\u00f3: <br\/> $ A={{(x+2)}^{3}}-{{(x-2)}^{3}}-12{{x}^{2}} $<br\/>$ ={{x}^{3}}+6{{x}^{2}}+12x+8$$-\\left( {{x}^{3}}-6{{x}^{2}}+12x-8 \\right)-12{{x}^{2}} $<br\/>$ ={{x}^{3}}+6{{x}^{2}}+12x+8-{{x}^{3}}$$+6{{x}^{2}}-12x+8-12{{x}^{2}} $<br\/>$ =\\left( {{x}^{3}}-{{x}^{3}} \\right)+\\left( 6{{x}^{2}}+6{{x}^{2}}-12{{x}^{2}} \\right)$$+\\left( 12x-12x \\right)+8+8 $<br\/>$ =16 $ <br\/> Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c $A$ kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o $x$. <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 \u0110\u00fang.<\/span>","column":2}]}],"id_ques":505},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng ","title_trans":"","temp":"fill_the_blank","correct":[[["1"]]],"list":[{"point":5,"width":40,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/3.jpg' \/><\/center>Bi\u1ebft $(1-2x)(1+2x+4x^2)+7x^3=0$, khi \u0111\u00f3 $x = $_input_","hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>S\u1eed d\u1ee5ng h\u1eb1ng \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 h\u1ecdc \u0111\u1ec3 r\u00fat g\u1ecdn v\u1ebf tr\u00e1i v\u00e0 gi\u1ea3i t\u00ecm $x$.<br\/><span class='basic_green'>B\u00e0i gi\u1ea3i<\/span><br\/> Ta c\u00f3:<br\/> $ (1-2x)(1+2x+4{{x}^{2}})$$+7{{x}^{3}}=0 $<br\/>$ 1-{{\\left( 2x \\right)}^{3}}$$+7{{x}^{3}}=0 $<br\/>$ 1-8{{x}^{3}}+7{{x}^{3}}=0 $<br\/>$ 1-{{x}^{3}}=0 $<br\/>$ {{x}^{3}}=1 $<br\/>$ x=1 $. <br\/> <span class='basic_pink'> Do \u0111\u00f3 ph\u1ea3i \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $1$. <\/span><\/span> "}]}],"id_ques":506},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng ","title_trans":"","temp":"fill_the_blank","correct":[[["2"]]],"list":[{"point":5,"width":40,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/3.jpg' \/><\/center>Bi\u1ebft $(x+2)(x^2-2x+4)$$-x(x-3)(x+3)=26$, khi \u0111\u00f3 $x =$ _input_","hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn<\/span><br\/>S\u1eed d\u1ee5ng c\u00e1c h\u1eb1ng \u0111\u1eb3ng th\u1ee9c \u0111\u00e3 h\u1ecdc r\u00fat g\u1ecdn v\u1ebf tr\u00e1i v\u00e0 t\u00ecm $x$.<br\/><span class='basic_green'>B\u00e0i gi\u1ea3i<\/span><br\/> Ta c\u00f3:<br\/> $ (x+2)({{x}^{2}}-2x+4)-x(x-3)(x+3) =26 $<br\/>$ {{x}^{3}}+{{2}^{3}}-x\\left( {{x}^{2}}-9 \\right) =26 $<br\/>$ {{x}^{3}}+8-{{x}^{3}}+9x=26 $<br\/>$ 9x=26-8 $<br\/>$ 9x=18 $<br\/>$ x=2 $ . <br\/> <span class='basic_pink'> Do \u0111\u00f3 ph\u1ea3i \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $2$. <\/span><\/span> "}]}],"id_ques":507},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng ","title_trans":"","temp":"fill_the_blank","correct":[[["-7"]]],"list":[{"point":5,"width":40,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/2.jpg' \/><\/center> Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c $\\left( \\dfrac{1}{9}{{x}^{2}}-\\dfrac{1}{3}xy+{{y}^{2}} \\right)\\left( \\dfrac{1}{3}x+y \\right)$ v\u1edbi $x = 3; y = -2$ l\u00e0 _input_","hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/><b>B\u01b0\u1edbc 1:<\/b> R\u00fat g\u1ecdn bi\u1ec3u th\u1ee9c v\u1ec1 d\u1ea1ng $a^3+b^3$.<br\/> <b>B\u01b0\u1edbc 2:<\/b> Thay $x = 3; y = -2$ v\u00e0o bi\u1ec3u th\u1ee9c \u0111\u1ec3 t\u00ednh gi\u00e1 tr\u1ecb.<br\/><span class='basic_green'>B\u00e0i gi\u1ea3i<\/span><br\/> Ta c\u00f3: <br\/> $\\left( \\dfrac{1}{9}{{x}^{2}}-\\dfrac{1}{3}xy+{{y}^{2}} \\right)\\left( \\dfrac{1}{3}x+y \\right)$$={{\\left( \\dfrac{1}{3}x \\right)}^{3}}+{{y}^{3}}$ <br\/> Thay $x = 3; y = -2$ v\u00e0o ta \u0111\u01b0\u1ee3c: <br\/> ${{\\left( \\dfrac{1}{3}x \\right)}^{3}}+{{y}^{3}} ={{\\left( \\dfrac{1}{3}.3 \\right)}^{3}}+{{(-2)}^{3}}=1^3 - 8= -7 $. <br\/> <span class='basic_pink'> Do \u0111\u00f3 s\u1ed1 ph\u1ea3i \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $-7$. <\/span><\/span> "}]}],"id_ques":508},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng ","title_trans":"","temp":"fill_the_blank","correct":[[["-513"],["8"]]],"list":[{"point":5,"width":40,"type_input":"","input_hint":["frac"],"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/2.jpg' \/><\/center> Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c $\\left( xy-\\dfrac{1}{2} \\right)\\left( {{x}^{2}}{{y}^{2}}+\\dfrac{1}{2}xy+\\dfrac{1}{4} \\right)$ v\u1edbi $x = 2; y = -2$ l\u00e0 <div class=\"frac123\"><div class=\"ts\">_input_<\/div><div class=\"ms\">_input_<\/div><\/div>","hint":"R\u00fat g\u1ecdn bi\u1ec3u th\u1ee9c sau \u0111\u00f3 thay $x = 2; y = -2$ v\u00e0o bi\u1ec3u th\u1ee9c \u0111\u1ec3 t\u00ednh gi\u00e1 tr\u1ecb.","explain":"<span class='basic_left'>Ta c\u00f3:<br\/> $\\left( xy-\\dfrac{1}{2} \\right)\\left( {{x}^{2}}{{y}^{2}}+\\dfrac{1}{2}xy+\\dfrac{1}{4} \\right)$$={{\\left( xy \\right)}^{3}}-{{\\left( \\dfrac{1}{2} \\right)}^{8}}$$={{\\left( xy \\right)}^{3}}-\\dfrac{1}{8}$ <br\/> Thay $x = 2; y = -2$ v\u00e0o bi\u1ec3u th\u1ee9c sau khi thu g\u1ecdn, ta \u0111\u01b0\u1ee3c: <br\/> ${\\left[ 2.(-2) \\right]}^{3}-\\dfrac{1}{8} ={{\\left( -4 \\right)}^{3}}-\\dfrac{1}{8}=\\dfrac{-513}{8}$.<\/span> "}]}],"id_ques":509},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng ","title_trans":"","temp":"fill_the_blank","correct":[[["0"]]],"list":[{"point":5,"width":40,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/5.jpg' \/><\/center> Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c $(x^2-y^2)(x^4+x^2y^2+y^4)$ v\u1edbi $x = y = 1$ l\u00e0 _input_","hint":"","explain":"<span class='basic_left'>Ta c\u00f3: <br\/> $(x^2-y^2)(x^4+x^2y^2+y^4)=x^6-y^6$ <br\/> Thay $x = y = 1$ v\u00e0o bi\u1ec3u th\u1ee9c sau khi thu g\u1ecdn, ta \u0111\u01b0\u1ee3c: <br\/> $1^6-1^6=1-1=0$. <br\/> <span class='basic_pink'> Do \u0111\u00f3 ph\u1ea3i \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $0$. <\/span><\/span> "}]}],"id_ques":510},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t<br\/> \u0110\u01b0a v\u1ec1 d\u1ea1ng h\u1eb1ng \u0111\u1eb3ng th\u1ee9c $a^3-b^3$ ho\u1eb7c $a^3+b^3$","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/3.jpg' \/><\/center>$(a^3-b^2)(a^6+a^3b^2+b^4) = ?$","select":["A. $a^3-b^2$ ","B. $a^9-b^6$ ","C. $a^6-b^4$","D. $a^6-b^6$"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn<\/span><br\/> <b>B\u01b0\u1edbc 1:<\/b> \u00c1p d\u1ee5ng h\u1eb1ng \u0111\u1eb3ng th\u1ee9c d\u1ea1ng $a^3-b^3$<br\/><b>B\u01b0\u1edbc 2:<\/b>T\u00ecm \u0111\u01b0\u1ee3c $a$ v\u00e0 $b$ <br\/><span class='basic_green'>Gi\u1ea3i<\/span><br\/><span class='basic_left'> Ta c\u00f3: <br\/> $(a^3-b^2)(a^6+a^3b^2+b^4)$$=(a^3)^3-(b^2)^3=a^9-b^6$ .<span><br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 B.<\/span>","column":2}]}],"id_ques":511},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t<br\/> \u0110\u01b0a v\u1ec1 d\u1ea1ng h\u1eb1ng \u0111\u1eb3ng th\u1ee9c $a^3-b^3$ ho\u1eb7c $a^3+b^3$","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/4.jpg' \/><\/center>$(a^2b^2+1)(a^4b^4-a^2b^2+1) = ?$","select":["A. $a^8b^8+1$ ","B. $a^2b^2+1$ ","C. $a^6b^6+1$","D. $a^4b^4+1$"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn<\/span><br\/> <b>B\u01b0\u1edbc 1:<\/b> Nh\u1eadn \u0111\u1ecbnh \u0111\u00e2y l\u00e0 h\u1eb1ng \u0111\u1eb3ng th\u1ee9c d\u1ea1ng $a^3+b^3$<br\/><b>B\u01b0\u1edbc 2:<\/b> T\u00ecm \u0111\u01b0\u1ee3c $a$ v\u00e0 $b$.<br\/><span class='basic_green'>B\u00e0i gi\u1ea3i<\/span><br\/> $(a^2b^2+1)(a^4b^4-a^2b^2+1)=(a^2b^2)^3+1=a^6b^6+1$ .<span><br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 C.<\/span>","column":2}]}],"id_ques":512},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u + ho\u1eb7c - v\u00e0o \u00f4 tr\u1ed1ng \u0111\u1ec3 \u0111\u01b0\u1ee3c m\u1ed9t khai tri\u1ec3n \u0111\u00fang ","title_trans":"","temp":"fill_the_blank","correct":[[["+"],["-"],["+"]]],"list":[{"point":5,"width":40,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/5.jpg' \/><\/center>$\\dfrac{27}{64}{{x}^{6}}+64$$=(\\dfrac{3}{4}{{x}^{2}}\\,\\,\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}\\,\\,4)(\\dfrac{9}{16}{{x}^{4}}\\,\\,\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}\\,\\,3x^2\\,\\,\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}\\,\\,16)$ ","hint":"Ta khai tri\u1ec3n $\\dfrac{27}{64}{{x}^{6}}+64$ theo h\u1eb1ng \u0111\u1eb3ng th\u1ee9c: $a^3+b^3$, t\u1eeb \u0111\u00f3 t\u00ecm ra c\u00e1c d\u1ea5u c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng.","explain":"<span class='basic_left'>Ta khai tri\u1ec3n v\u1ebf tr\u00e1i: <br\/>$\\dfrac{27}{64}{{x}^{6}}+64={{\\left( \\dfrac{3}{4}{{x}^{2}} \\right)}^{3}}+{{4}^{3}}$$=\\left( \\dfrac{3}{4}{{x}^{2}}+4 \\right)\\left( \\dfrac{9}{16}{{x}^{4}}-3{{x}^{2}}+16 \\right)$. <br\/> <span class='basic_pink'> Do \u0111\u00f3 ph\u1ea3i \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u1ea7n l\u01b0\u1ee3t c\u00e1c d\u1ea5u $+, -$ v\u00e0 $+$. <\/span><\/span> "}]}],"id_ques":513},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u $+$ ho\u1eb7c $-$ v\u00e0o \u00f4 tr\u1ed1ng \u0111\u1ec3 \u0111\u01b0\u1ee3c m\u1ed9t khai tri\u1ec3n \u0111\u00fang ","title_trans":"","temp":"fill_the_blank","correct":[[["-"],["+"],["+"]]],"list":[{"point":5,"width":40,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/5.jpg' \/><\/center>${{a}^{3}}{{b}^{3}}-\\dfrac{1}{8}$$=\\left( ab\\,\\,\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}\\,\\,\\dfrac{1}{2} \\right)\\left( {{a}^{2}}{{b}^{2}}\\,\\,\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}\\,\\,\\dfrac{1}{2}ab\\,\\,\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}\\,\\,\\dfrac{1}{4} \\right)$ ","hint":"Ta khai tri\u1ec3n ${{a}^{3}}{{b}^{3}}-\\dfrac{1}{8}$ theo h\u1eb1ng \u0111\u1eb3ng th\u1ee9c: $a^3-b^3$, t\u1eeb \u0111\u00f3 t\u00ecm ra c\u00e1c d\u1ea5u c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng.","explain":"<span class='basic_left'>Ta khai tri\u1ec3n v\u1ebf tr\u00e1i: <br\/>${{a}^{3}}{{b}^{3}}-\\dfrac{1}{8}={{\\left( ab \\right)}^{3}}-{{\\left( \\dfrac{1}{2} \\right)}^{3}}$$=\\left( ab-\\dfrac{1}{2} \\right)\\left( {{a}^{2}}{{b}^{2}}+\\dfrac{1}{2}ab+\\dfrac{1}{4} \\right)$. <br\/> <span class='basic_pink'> Do \u0111\u00f3 ph\u1ea3i \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u1ea7n l\u01b0\u1ee3t c\u00e1c d\u1ea5u $- , +$ v\u00e0 $+$. <\/span><\/span> "}]}],"id_ques":514},{"time":24,"part":[{"title":"Ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"select":["A. $x = 4a^2; y = 6ab; z = 9b^2$","B. $x = 4a^2; y = 4ab; z = 6b^2$","C. $x = a^2; y = 4ab; z = b^2$"],"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/2.jpg' \/><\/center> $(2a+3b)(\\,\\,\\,\\,x\\,\\,\\,\\,- y\\,\\,\\,\\, + z\\,\\,\\,\\,)=8a^3+27b^3$. T\u00ecm $x,y,z$","hint":"V\u1ebf tr\u00e1i l\u00e0 khai tri\u1ec3n c\u1ee7a h\u1eb1ng \u0111\u1eb3ng th\u1ee9c: $a^3+b^3$.<br\/> Ta khai tri\u1ec3n v\u1ebf ph\u1ea3i ng\u01b0\u1ee3c l\u1ea1i \u0111\u1ec3 t\u00ecm c\u00e1c y\u1ebfu t\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng.","explain":"<span class='basic_left'>Ta c\u00f3: <br\/> $8a^3+27b^3=(2a)^3+(3b)^3 =(2a+3b)(4a^2-6ab+9b^2)$.<\/span> "}]}],"id_ques":515},{"time":24,"part":[{"title":"\u0110i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng \u0111\u1ec3 \u0111\u01b0\u1ee3c m\u1ed9t khai tri\u1ec3n \u0111\u00fang ","title_trans":"","temp":"fill_the_blank","correct":[[["1","-5xy"],["-5xy","1"],["5xy"]]],"list":[{"point":5,"width":40,"type_input":"","input_hint":["sqr"],"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/5.jpg' \/><\/center> $1-125x^3y^3$$=(\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}+\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{})(1+\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}+25x^2y^2)$ ","hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn<\/span><br\/>V\u1ebf tr\u00e1i l\u00e0 h\u1eb1ng \u0111\u1eb3ng th\u1ee9c: $a^3-b^3$.<br\/> Ta khai tri\u1ec3n \u0111\u1ec3 t\u00ecm c\u00e1c y\u1ebfu t\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng. <br\/><span class='basic_green'>B\u00e0i gi\u1ea3i<\/span><br\/>Ta c\u00f3: <br\/> $1-125x^3y^3=1-(5xy)^3 = (1-5xy)(1+5xy+25x^2y^2)$ .<br\/> <span class='basic_pink'>V\u1eady c\u1ea7n \u0111i\u1ec1n l\u00e0 $1, -5xy$ v\u00e0 $5xy$. <\/span><\/span> "}]}],"id_ques":516},{"time":24,"part":[{"title":"\u0110i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng \u0111\u1ec3 \u0111\u01b0\u1ee3c m\u1ed9t khai tri\u1ec3n \u0111\u00fang ","title_trans":"","temp":"fill_the_blank_random","correct":[[["2a"],["-b"]]],"list":[{"point":5,"width":40,"type_input":"","input_hint":["sqr"],"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/5.jpg' \/><\/center> $8a^3-b^3$$=(\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}+\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{})(4a^2+2ab+b^2)$ ","hint":"V\u1ebf tr\u00e1i l\u00e0 h\u1eb1ng \u0111\u1eb3ng th\u1ee9c: $a^3-b^3=(a-b)(a^2+ab+b^2)$.<br\/> Ta khai tri\u1ec3n \u0111\u1ec3 t\u00ecm c\u00e1c y\u1ebfu t\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng. ","explain":"<span class='basic_left'> Ta c\u00f3: <br\/> $8a^3-b^3$$=(2a-b)(4a^2+2ab+b^2)$ .<br\/> <span class='basic_pink'>V\u1eady c\u1ea7n \u0111i\u1ec1n l\u00e0 $2a$ v\u00e0 $-b$. <\/span><\/span> "}]}],"id_ques":517},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/daiso/bai5/lv2/img\/4.jpg' \/><\/center>Khai tri\u1ec3n ${{x}^{3}}-\\dfrac{27}{8}{{y}^{3}}$ theo h\u1eb1ng \u0111\u1eb3ng th\u1ee9c ta \u0111\u01b0\u1ee3c:","select":["A. $\\left( x-\\dfrac{3}{2}y \\right)\\left( {{x}^{2}}+\\dfrac{3}{2}xy+\\dfrac{9}{4}{{y}^{2}} \\right)$ ","B. $\\left( x-\\dfrac{3}{8}y \\right)\\left( {{x}^{2}}+\\dfrac{3}{8}xy+\\dfrac{9}{64}{{y}^{2}} \\right)$ ","C. $\\left( x-\\dfrac{3}{2}y \\right)\\left( {{x}^{2}}+\\dfrac{3}{2}xy+\\dfrac{27}{8}{{y}^{2}} \\right)$","D. $\\left( x-\\dfrac{3}{8}y \\right)\\left( {{x}^{2}}-\\dfrac{3}{8}xy+\\dfrac{9}{64}{{y}^{2}} \\right)$"],"hint":"Khai tri\u1ec3n theo h\u1eb1ng \u0111\u1eb3ng th\u1ee9c: $a^3-b^3=(a-b)(a^2+ab+b^2)$.","explain":"<span class='basic_left'>Ta c\u00f3:<br\/> ${{x}^{3}}-\\dfrac{27}{8}{{y}^{3}}={{x}^{3}}-{{\\left( \\dfrac{3}{2}y \\right)}^{3}}$$=\\left( x-\\dfrac{3}{2}y \\right)\\left( {{x}^{2}}+\\dfrac{3}{2}xy+\\dfrac{9}{4}{{y}^{2}} \\right)$ .<span><br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 $A$.<\/span>","column":2}]}],"id_ques":518},{"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/bai5/lv2/img\/3.jpg' \/><\/center>Khai tri\u1ec3n $a^6-b^3$ theo h\u1eb1ng \u0111\u1eb3ng th\u1ee9c ta \u0111\u01b0\u1ee3c:","select":["A. $(a^3-b)(a^6+3a^3b+b^2)$ ","B. $(a^3-b)(a^6-a^3b+b^2)$ ","C. $(a^2-b)(a^4+a^2b+b^2)$","D. $(a^2-b)(a^4-a^2b+b^2)$"],"hint":"Khai tri\u1ec3n theo h\u1eb1ng \u0111\u1eb3ng th\u1ee9c:$a^3-b^3=(a-b)(a^2+ab+b^2)$.","explain":"<span class='basic_left'>Ta c\u00f3: <br\/> $a^6-b^3=(a^2)^3-b^3$$=(a^2-b)(a^4+a^2b+b^2)$ .<span><br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 C.<\/span>","column":2}]}],"id_ques":519},{"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/bai5/lv2/img\/3.jpg' \/><\/center>Khai tri\u1ec3n $\\dfrac{1}{64}+{{a}^{3}}$ theo h\u1eb1ng \u0111\u1eb3ng th\u1ee9c ta \u0111\u01b0\u1ee3c:","select":["A. $\\left( \\dfrac{1}{32}+a \\right)\\left( \\dfrac{1}{64}+\\dfrac{1}{32}a+{{a}^{2}} \\right)$ ","B. $\\left( \\dfrac{1}{4}+a \\right)\\left( \\dfrac{1}{16}-\\dfrac{1}{4}a+{{a}^{2}} \\right)$ ","C. $\\left( \\dfrac{1}{32}+a \\right)\\left( \\dfrac{1}{64}-\\dfrac{1}{32}a+{{a}^{2}} \\right)$","D. $\\left( \\dfrac{1}{4}+a \\right)\\left( \\dfrac{1}{16}+\\dfrac{1}{4}a+{{a}^{2}} \\right)$"],"hint":"Khai tri\u1ec3n theo h\u1eb1ng \u0111\u1eb3ng th\u1ee9c: $a^3+b^3=(a+b)(a^2-ab+b^2)$.","explain":"<span class='basic_left'>Ta c\u00f3:<br\/> $\\dfrac{1}{64}+{a}^{3}={\\left( \\dfrac{1}{4} \\right)}^{3}+{a}^{3} =\\left( \\dfrac{1}{4}+a \\right)\\left( \\dfrac{1}{16}-\\dfrac{1}{4}a+{{a}^{2}} \\right)$.<span><br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 B.<\/span>","column":2}]}],"id_ques":520}],"lesson":{"save":0,"level":2}}