a) 6x2 - 6xy - 4x + 4y= 6x (x - y) - 4 (x - y)= (x - y) (6x - 4)b) x3 + 10x2 + 25x - xy2= x (x2 + 10x + 25 - y2)= x [(x + 5)2 - y2]= x (x + 5 + y) (x + 5 - y)

a, \(6x^2-6xy-4x+4y=6x\left(x-y\right)-4\left(x-y\right)=\left(6x-4\right)\left(x-y\right)\)

b, \(x^3+10x^2+25x-xy^2=x\left(x^2+10x+25-y^2\right)\)

\(=x\left[\left(x+5\right)-y^2\right]=x\left(x+5-y\right)\left(x+5+y\right)\)

mi mà ko làm đc là thầy cô cho ăn lòn đớ

\(B=-2xy^2+\left(2xy-2x\right)\left(y+1\right)\)\(B=-2xy^2+2xy^2+2xy-2xy-2x=-2x\) Không phụ thuộc biến y

\(x^2-8x+9=0\)\(\Rightarrow x^2-9x+x+9=0\)\(\Rightarrow x^2+x-9x+9=0\)\(\Rightarrow x\left(x+1\right)-9\left(x+1\right)=0\)\(\Rightarrow\left(x+1\right)\left(x-9\right)=0\)\(\Rightarrow\orbr{\begin{cases}x+1=0\\x-9=0\end{cases}\Rightarrow\orbr{\begin{cases}x=-1\\x=9\end{cases}}}\)Có j sai thông cẻm :>>

x2-8x+9= x2-9x+x+9=x(x+1)-9(x+1)=(x+1)(x-9) x+1=0=>x=-1 hoặc x-9=0=>x=9

Chắc hết lỗi rồi, xin trình bày lại

Ta có: \(c^2+a^2+b^2+\frac{1}{a^2}+\frac{1}{b^2}+\frac{1}{c^2}\)

\(=\left(a^2+\frac{1}{a^2}\right)+\left(b^2+\frac{1}{b^2}\right)+\left(c^2+\frac{1}{c^2}\right)\)

\(\ge2\sqrt{a^2\cdot\frac{1}{a^2}}+2\sqrt{b^2\cdot\frac{1}{b^2}}+2\sqrt{c^2\cdot\frac{1}{c^2}}\left(Cauchy\right)\)

\(=2+2+2=6\)

Dấu "=" xảy ra khi: \(a^4=b^4=c^4=1\Leftrightarrow a^{2020}=b^{2020}=c^{2020}=1\)

\(\Rightarrow B=a^{2020}+b^{2020}+c^{2020}=1+1+1=3\)

Vậy B = 3

(c^2+a^2+b^2+ rac{1}{a^2}+ rac{1}{b^2}+ rac{1}{c^2})(=left(a^2+ rac{1}{a^2} ight)+left(b^2+ rac{1}{b^2} ight)+left(c^2+ rac{1}{c^2} ight))(ge2sqrt{a^2cdot rac{1}{a^2}}+2sqrt{b^2cdot rac{1}{b^2}}+2sqrt{c^2cdot rac{1}{c^2}}) (Cauchy)(=2+2+2=6)Dấu "=" xảy ra khi: (a^2= rac{1}{a^2};b^2= rac{1}{b^2};c^2= rac{1}{c^2}Leftrightarrow a^4=b^4=c^4=1)(Leftrightarrow a^{2020}=b^{2020}=c^{2020}=1)(Rightarrow B=a^{2020}+b^{2020}+c^{2020}=1+1+1=3)

A = 4x² + 6x = 2x( 2x + 3 )

B = ( x + 5 )² - y² = ( x + 5 - y )( x + 5 + y )

C = x² + 2xy - 2x + y² - 2y = ( x² + 2xy + y² ) - ( 2x + 2y ) = ( x + y )² - 2( x + y ) = ( x + y )( x + y - 2 )

D = x² - 4x + 3 = x² - x - 3x + 3 = ( x² - x ) - ( 3x - 3 ) = x( x - 1 ) - 3( x - 1 ) = ( x - 1 )( x - 3 )

a)4x^2+6x

=2x(2x+3)

b)(x+5)^2-y^2

=(x+5-y)(x+5+y)

c)x^2+2xy-2x+y^2-2y

=(x^2+2xy+y^2)-(2x+2y)

=(x+y)^2-2(x+y)

=(x+y)(x+y-2)

d)x^2-4x+3

=(x^2-x)-(3x-3)

=x(x-1)-3(x-1)

=(x-3)(x-1)

a)x(x-1)

=x^2-x

b)(x+3y)(x-3y+2)

=x^2+3xy-3xy-9y^2+2x+6y

=x^2-9y^2+2x+6y

c)(x+3)^2

=x^2+6x+9

d)(3x-2)(3x+2)-9x^2

=9x^2-4-9x^2

=-4