đang tải bài tập bài
{"segment":[{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":10,"ques":"<span class='basic_left'> T\u00ednh gi\u00e1 tr\u1ecb c\u1ee7a \u0111a th\u1ee9c $D=(a+b)(a+1)(b+1)$ bi\u1ebft $a+b=3$ v\u00e0 $ab=-5.$ <br\/> Gi\u00e1 tr\u1ecb c\u1ee7a \u0111a th\u1ee9c $D$ l\u00e0: <\/span>","select":["A. $5$","B. $-3$","C. $-5$ ","D. $3$"],"explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> - Thay $a+b=3$ v\u00e0o $D.$ <br\/> - Khai tri\u1ec3n $(a+1)(b+1)$ r\u1ed3i thay $a+b=3;ab=-5$ v\u00e0o \u0111\u1ec3 t\u00ednh. <br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3: <br\/> $\\begin{align} & D=(a+b)(a+1)(b+1) \\\\ & \\,\\,\\,\\,\\,\\,=3\\left( a+1 \\right)\\left( b+1 \\right)\\,\\,(do\\,\\,a+b=3) \\\\ & \\,\\,\\,\\,\\,\\,=3\\left( ab+a+b+1 \\right) \\\\ & \\,\\,\\,\\,\\,\\,=3\\left( -5+3+1 \\right) \\,\\,(do \\,\\,a+b=3;ab=-5) \\\\ & \\,\\,\\,\\,\\,\\,=3.\\left( -1 \\right) \\\\ & \\,\\,\\,\\,\\,\\,=-3 \\\\ \\end{align}$ <br\/><span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 B.<\/span><\/span>","column":4}]}],"id_ques":1291},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":10,"ques":"<span class='basic_left'> T\u00ednh gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c <br\/> $E={{x}^{10}}-2009{{x}^{9}}-2009{{x}^{8}}-...-2009x-1$ bi\u1ebft $x=2010$ <br\/> Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c $E$ l\u00e0: <\/span>","select":["A. $0$","B. $-1$","C. $2009$ ","D. $2010$"],"explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> - \u0110\u00e1nh gi\u00e1 v\u1edbi $x=2010$ th\u00ec $x-1=2009$ <br\/> - Do \u0111\u00f3 ta thay $2009$ b\u1eb1ng $x-1$ v\u00e0o bi\u1ec3u th\u1ee9c $E$, bi\u1ebfn \u0111\u1ed5i r\u1ed3i t\u00ecm gi\u00e1 tr\u1ecb c\u1ee7a $E$ <br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> Ta c\u00f3 $x=2010 \\Rightarrow x-1=2009$ <br\/> Thay $2009$ b\u1eb1ng $x-1$ v\u00e0o $E$ ta \u0111\u01b0\u1ee3c: <br\/> $\\begin{align} & E={{x}^{10}}-2009{{x}^{9}}-2009{{x}^{8}}-...-2009x-1 \\\\ & \\,\\,\\,\\,\\,={{x}^{10}}-\\left( x-1 \\right){{x}^{9}}-\\left( x-1 \\right){{x}^{8}}-...-\\left( x-1 \\right)x-1 \\\\ & \\,\\,\\,\\,\\,={{x}^{10}}-{{x}^{10}}+{{x}^{9}}-{{x}^{9}}+{{x}^{8}}-...-{{x}^{2}}+x-1 \\\\ & \\,\\,\\,\\,\\,=x-1 \\\\ & \\,\\,\\,\\,\\,=2009 \\\\ \\end{align}$ <br\/><span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 C.<\/span><\/span>","column":4}]}],"id_ques":1292},{"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","correct":[[["2"]]],"list":[{"point":10,"width":40,"content":"","type_input":"","ques":" <span class='basic_left'> T\u00ecm gi\u00e1 tr\u1ecb nguy\u00ean c\u1ee7a bi\u1ebfn $x$ \u0111\u1ec3 bi\u1ec3u th\u1ee9c $B=\\dfrac{8-x}{x-3}$ c\u00f3 gi\u00e1 tr\u1ecb nh\u1ecf nh\u1ea5t. <br\/> <b> \u0110\u00e1p \u00e1n:<\/b> $x=\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}$ <\/span> ","hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> Ph\u00e2n t\u00edch $B$ th\u00e0nh d\u1ea1ng $a+\\dfrac{b}{3-x}$, trong \u0111\u00f3 $a,b$ l\u00e0 c\u00e1c s\u1ed1 nguy\u00ean \u00e2m. <br\/> T\u00ecm gi\u00e1 tr\u1ecb c\u1ee7a $\\dfrac{b}{3-x}$ \u0111\u1ec3 $B$ c\u00f3 gi\u00e1 tr\u1ecb nh\u1ecf nh\u1ea5t. <br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> Ta c\u00f3: <br\/> $B=\\dfrac{8-x}{x-3}=\\dfrac{-\\left( x-8 \\right)}{x-3}=\\dfrac{-\\left( x-3-5 \\right)}{x-3}=-1+\\dfrac{5}{x-3}=-1-\\dfrac{5}{3-x}$ <br\/> \u0110\u1ec3 $B$ nh\u1ecf nh\u1ea5t th\u00ec $\\dfrac{5}{3-x}$ ph\u1ea3i l\u00e0 s\u1ed1 nguy\u00ean d\u01b0\u01a1ng l\u1edbn nh\u1ea5t <br\/> $\\Rightarrow 3-x=1 \\Rightarrow x=2$ <br\/> <span class='basic_pink'> V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $2$<\/span><\/span>"}]}],"id_ques":1293},{"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","correct":[[["-83"],["11"]]],"list":[{"point":10,"width":40,"content":"","type_input":"","input_hint":["frac"],"ques":"Cho <br\/> $\\begin{align} & F\\left( x \\right)={{x}^{3}}-2ax+{{a}^{2}} \\\\ & G\\left( x \\right)={{x}^{4}}+\\left( 3a+1 \\right)x+{{a}^{2}} \\\\ \\end{align}$ <br\/> T\u00ecm $a$ sao cho $F(1)=G(3).$<br\/> <b> \u0110\u00e1p \u00e1n:<\/b> $a=$ <div class=\"frac123\"><div class=\"ts\">_input_<\/div><div class=\"ms\">_input_<\/div><\/div>","hint":"","explain":"<span class='basic_left'> Ta c\u00f3: <br\/> $\\begin{align} & F\\left( 1 \\right)=G\\left( 3 \\right) \\\\ & \\Rightarrow {{1}^{3}}-2a.1+{{a}^{2}}={{3}^{4}}+\\left( 3a+1 \\right).3+{{a}^{2}} \\\\ & \\Rightarrow 1-2a+{{a}^{2}}=81+9a+3+{{a}^{2}} \\\\ & \\Rightarrow 11a+83=0 \\\\ & \\Rightarrow a=\\dfrac{-83}{11} \\\\ \\end{align}$<\/span>"}]}],"id_ques":1294},{"time":24,"part":[{"title":"Kh\u1eb3ng \u0111\u1ecbnh sau \u0111\u00e2y \u0110\u00fang hay Sai","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":10,"ques":" <span class='basic_left'> X\u00e9t \u0111a th\u1ee9c $P(x)=ax^2+bx+c\\,(a\\ne 0)$ <br\/> N\u1ebfu $a+b+c=0$ th\u00ec $P(x)$ c\u00f3 hai nghi\u1ec7m l\u00e0 $1$ v\u00e0 $\\dfrac{c}{a}.$<\/span>","select":["\u0110\u00fang","Sai "],"hint":"Thay $x=1;x=\\dfrac{c}{a}$ v\u00e0o $P(x)$ \u0111\u1ec3 ki\u1ec3m tra xem ch\u00fang c\u00f3 l\u00e0 nghi\u1ec7m c\u1ee7a \u0111a th\u1ee9c $P(x)$","explain":"<span class='basic_left'> Thay $x=1$ v\u00e0o \u0111a th\u1ee9c $P(x)$ ta \u0111\u01b0\u1ee3c: <br\/> $a.1^2+b.1+c=a+b+c=0$ (v\u00ec $a+b+c=0$ theo gi\u1ea3 thi\u1ebft) <br\/> Do \u0111\u00f3, $x=1$ l\u00e0 nghi\u1ec7m c\u1ee7a \u0111a th\u1ee9c $P(x)$ <br\/> Thay $x=\\dfrac{c}{a}$ v\u00e0o \u0111a th\u1ee9c $P(x)$ ta \u0111\u01b0\u1ee3c: <br\/> $\\begin{align} a.{{\\left( \\dfrac{c}{a} \\right)}^{2}}+b.\\dfrac{c}{a}+c &=\\dfrac{{{c}^{2}}}{a}+\\dfrac{bc}{a}+c \\\\ & =\\dfrac{{{c}^{2}}+bc+ac}{a} \\\\ & =\\dfrac{c\\left( c+b+a \\right)}{a} \\\\ & =0 \\\\ \\end{align}$ <br\/> (v\u00ec $a+b+c=0$ theo gi\u1ea3 thi\u1ebft) <br\/> Do \u0111\u00f3, $x=\\dfrac{c}{a}$ l\u00e0 nghi\u1ec7m c\u1ee7a \u0111a th\u1ee9c $P(x)$ <br\/><span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 \u0110\u00fang.<\/span><\/span>","column":2}]}],"id_ques":1295},{"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"],["-1"]]],"list":[{"point":10,"width":40,"content":"","type_input":"","ques":" <span class='basic_left'> T\u00ecm nghi\u1ec7m c\u1ee7a \u0111a th\u1ee9c $(2x^2-3x+1)+(3x^2+3x-6)$ <br\/> <b> \u0110\u00e1p \u00e1n:<\/b> $\\left[ \\begin{align} & x=\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{} \\\\ & x=\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{} \\\\ \\end{align} \\right. $ <\/span> ","hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> Cho \u0111a th\u1ee9c b\u1eb1ng $0$ r\u1ed3i bi\u1ebfn \u0111\u1ed5i t\u00ecm nghi\u1ec7m c\u1ee7a \u0111a th\u1ee9c \u0111\u00f3. <br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> Ta c\u00f3: <br\/> $\\begin{aligned} & \\left( 2{{x}^{2}}-3x+1 \\right)+\\left( 3{{x}^{2}}+3x-6 \\right)=0 \\\\ & \\Rightarrow \\left( 2{{x}^{2}}+3{{x}^{2}} \\right)+\\left( -3x+3x \\right)+\\left( 1-6 \\right)=0 \\\\ & \\Rightarrow 5{{x}^{2}}-5=0 \\\\ & \\Rightarrow 5{{x}^{2}}=5 \\\\ & \\Rightarrow {{x}^{2}}=1 \\\\ & \\Rightarrow \\left[ \\begin{aligned} & x=1 \\\\ & x=-1 \\\\ \\end{aligned} \\right. \\\\ \\end{aligned}$ <br\/> <span class='basic_pink'> V\u1eady c\u00e1c s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $1;-1$<\/span><\/span>"}]}],"id_ques":1296},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":10,"ques":"<span class='basic_left'> Cho $x^2+y^2=1$ <br\/> Gi\u00e1 tr\u1ecb c\u1ee7a \u0111a th\u1ee9c $2x^4+3x^2y^2+y^4+y^2$ l\u00e0: <\/span>","select":["A. $1$","B. $2$","C. $3$ ","D. $4$"],"hint":"T\u00e1ch $3x^2y^2=2x^2y^2+x^2y^2$","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> - T\u00e1ch $3x^2y^2=2x^2y^2+x^2y^2$ <br\/> - Nh\u00f3m c\u00e1c h\u1ea1ng t\u1eed v\u1edbi nhau th\u00e0nh t\u1eebng c\u1eb7p <br\/> - V\u1edbi t\u01b0ng c\u1eb7p, ta ph\u00e2n t\u00edch \u0111\u1ec3 l\u00e0m xu\u1ea5t hi\u1ec7n $x^2+y^2$ <br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3: <br\/> $\\begin{align} & 2{{x}^{4}}+3{{x}^{2}}{{y}^{2}}+{{y}^{4}}+{{y}^{2}} \\\\ & =(2{{x}^{4}}+2{{x}^{2}}{{y}^{2}})+({{x}^{2}}{{y}^{2}}+{{y}^{4}})+{{y}^{2}} \\\\ & =2{{x}^{2}}\\left( {{x}^{2}}+{{y}^{2}} \\right)+{{y}^{2}}\\left( {{x}^{2}}+{{y}^{2}} \\right)+{{y}^{2}} \\\\ & =2{{x}^{2}}.1+{{y}^{2}}.1+{{y}^{2}}\\,\\,\\,\\left( do\\,\\,{{x}^{2}}+{{y}^{2}}=1 \\right) \\\\ & =2{{x}^{2}}+{{y}^{2}}+{{y}^{2}} \\\\ & =\\left( {{x}^{2}}+{{y}^{2}} \\right)+\\left( {{x}^{2}}+{{y}^{2}} \\right) \\\\ & =1+1 \\\\ & =2 \\\\ \\end{align}$ <br\/><span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 B.<\/span> <\/span>","column":4}]}],"id_ques":1297},{"time":24,"part":[{"title":"Kh\u1eb3ng \u0111\u1ecbnh sau \u0111\u00e2y \u0110\u00fang hay Sai","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":10,"ques":" <span class='basic_left'> \u0110a th\u1ee9c $A(x)$ c\u00f3 \u00edt nh\u1ea5t ba nghi\u1ec7m n\u1ebfu bi\u1ebft: <br\/> $(x^2-4)A(x)=x.A(x-3)$<\/span>","select":["\u0110\u00fang","Sai "],"hint":"","explain":"<span class='basic_left'> Khi $x=2$ th\u00ec $(2^2-4)A(2)=2.A(2-3) \\Rightarrow A(-1)=0$ <br\/> Do \u0111\u00f3, $x=-1$ l\u00e0 m\u1ed9t nghi\u1ec7m c\u1ee7a \u0111a th\u1ee9c $A(x)$ <br\/> Khi $x=-2$ th\u00ec $[(-2)^2-4]A(-2)=(-2).A(-2-3) \\Rightarrow A(-5)=0$ <br\/> Do \u0111\u00f3, $x=-2$ l\u00e0 m\u1ed9t nghi\u1ec7m c\u1ee7a \u0111a th\u1ee9c $A(x)$<br\/> Khi $x=0$ th\u00ec $(0^2-4)A(0)=0.A(0-3) \\Rightarrow A(0)=0$ <br\/> Do \u0111\u00f3, $x=0$ l\u00e0 m\u1ed9t nghi\u1ec7m c\u1ee7a \u0111a th\u1ee9c $A(x)$ <br\/> V\u1eady \u0111a th\u1ee9c $A(x)$ c\u00f3 \u00edt nh\u1ea5t ba nghi\u1ec7m n\u1ebfu $(x^2-4)A(x)=x.A(x-3)$ <br\/><span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 \u0110\u00fang.<\/span><\/span>","column":2}]}],"id_ques":1298},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":10,"ques":"<span class='basic_left'> S\u1ed1 nghi\u1ec7m c\u1ee7a \u0111a th\u1ee9c $x^2-6x+10$ l\u00e0: <\/span>","select":["A. $1$","B. $2$","C. Kh\u00f4ng c\u00f3 nghi\u1ec7m"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> - T\u00e1ch $-6x=-3x-3x;10=9+1$ <br\/> - Nh\u00f3m c\u00e1c h\u1ea1ng t\u1eed v\u1edbi nhau th\u00e0nh t\u1eebng c\u1eb7p <br\/> - Ph\u00e2n t\u00edch, nh\u1eadn \u0111\u1ecbnh \u0111\u01b0a ra s\u1ed1 nghi\u1ec7m c\u1ee7a \u0111a th\u1ee9c. <br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3: <br\/> $\\begin{align} & {{x}^{2}}-6x+10 \\\\ & ={{x}^{2}}-3x-3x+9+1 \\\\ & =\\left( {{x}^{2}}-3x \\right)-\\left( 3x-9 \\right)+1 \\\\ & =x\\left( x-3 \\right)-3\\left( x-3 \\right)+1 \\\\ & =\\left( x-3 \\right)\\left( x-3 \\right)+1 \\\\ & ={{\\left( x-3 \\right)}^{2}}+1 \\\\ & Do\\,\\,{{\\left( x-3 \\right)}^{2}}\\,\\ge 0\\,\\,\\forall x \\\\ & \\Rightarrow {{\\left( x-3 \\right)}^{2}}+1\\ge 1>0 \\\\ \\end{align}$ <br\/> V\u1eady kh\u00f4ng c\u00f3 gi\u00e1 tr\u1ecb n\u00e0o c\u1ee7a $x$ \u0111\u1ec3 gi\u00e1 tr\u1ecb c\u1ee7a \u0111a th\u1ee9c $x^2-6x+10$ b\u1eb1ng $0$ <br\/> Do \u0111\u00f3, \u0111a th\u1ee9c $x^2-6x+10$ kh\u00f4ng c\u00f3 nghi\u1ec7m. <br\/><span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 C.<\/span> <\/span>","column":3}]}],"id_ques":1299},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":10,"ques":"<span class='basic_left'> T\u00ednh gi\u00e1 tr\u1ecb c\u1ee7a \u0111a th\u1ee9c $M=12x^2+20x+1,$ bi\u1ebft $3x^2+5x-2=0.$ <\/span>","select":["A. $M=9$ v\u00e0 $M=2$","B. $M=-5$","C. $M=0$","D. $M=9$"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1:<\/b> T\u00ecm gi\u00e1 tr\u1ecb c\u1ee7a $x$ t\u1eeb $3x^2+5x-2=0.$ <br\/> V\u1ebf tr\u00e1i: <br\/> - T\u00e1ch $5x=6x-x$ <br\/> - Nh\u00f3m th\u00e0nh t\u1eebng c\u1eb7p v\u1edbi nhau r\u1ed3i bi\u1ebfn \u0111\u1ed5i. <br\/> <b> B\u01b0\u1edbc 2:<\/b> Thay gi\u00e1 tr\u1ecb $x$ v\u1eeba t\u00ecm \u0111\u01b0\u1ee3c v\u00e0o \u0111a th\u1ee9c $M$ <br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3: <br\/> $\\begin{aligned} & 3{{x}^{2}}+5x-2=0 \\\\ & \\Rightarrow 3{{x}^{2}}+6x-x-2=0 \\\\ & \\Rightarrow \\left( 3{{x}^{2}}+6x \\right)-\\left( x+2 \\right)=0 \\\\ & \\Rightarrow 3x\\left( x+2 \\right)-\\left( x+2 \\right)=0 \\\\ & \\Rightarrow \\left( x+2 \\right)\\left( 3x-1 \\right)=0 \\\\ & \\Rightarrow \\left[ \\begin{aligned} & x+2=0 \\\\ & 3x-1=0 \\\\ \\end{aligned} \\right.\\Rightarrow \\left[ \\begin{aligned} & x=-2 \\\\ & x=\\dfrac{1}{3} \\\\ \\end{aligned} \\right. \\\\ \\end{aligned}$ <br\/> Thay $x=-2$ v\u00e0o $M$ ta \u0111\u01b0\u1ee3c: <br\/> $12.(-2)^2+20.(-2)+1=9$ <br\/> Thay $x=\\dfrac{1}{3}$ v\u00e0o $M$ ta \u0111\u01b0\u1ee3c: <br\/> $12.{{\\left( \\dfrac{1}{3} \\right)}^{2}}+20.\\dfrac{1}{3}+1=9$ <br\/><span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 D.<\/span> <br\/> <b> C\u00e1ch kh\u00e1c<\/b> <br\/> Ta c\u00f3 th\u1ec3 t\u00ecm gi\u00e1 tr\u1ecb c\u1ee7a $M$ nh\u01b0 sau: <br\/> $\\begin{align} & 12{{x}^{2}}+20x+1 \\\\ & =\\left( 12{{x}^{2}}+20x-8 \\right)+9 \\\\ & =4\\left( 3{{x}^{2}}+5x-2 \\right)+9 \\\\ & =4.0+9\\,\\,\\,\\left( do\\,\\,\\,3{{x}^{2}}+5x-2=0 \\right) \\\\ & =9 \\\\ \\end{align}$ <\/span>","column":2}]}],"id_ques":1300}],"lesson":{"save":0,"level":3}}

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