c ) x² +4x+4-y²

<=>(x+2)²-y²

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

d) \(5x-5y+ax-ay=5\left(x-y\right)+a\left(x-y\right)=\left(x-y\right)\left(5+a\right)\)

a) 

5x-5y+ax-ay = 5(x-y) +a(x-y) = (x-y)(5+a)

b) a^3 -a^2x-ay+xy = a^2(a-x) -y(a-x) = (a-x)(a^2-y)

c) xy(x+y) +yz(y+z) +xz(x+z) +2xyz = x^2.y+xy^2 +y^2.z+xz^2 +x^2.z+xz^2 +2xyz

= (x^2.y+x^2.z)+(xy^2+xz^2+2xyz)+(y^2.z+yz^2) = x^2(y+z) +x.(y+z)^2 +yz(y+z)

=(y+z)(x^2+x+yz)

\(1,=\left(x-3\right)\left(x+3\right)\\ 2,=\left(x-y\right)\left(5+a\right)\\ 3,=\left(x+3\right)^2\\ 4,=\left(x-y\right)\left(10x+7y\right)\\ 5,=5\left(x-3y\right)\\ 6,=\left(x-y\right)^2-z^2=\left(x-y-z\right)\left(x-y+z\right)\)

bạn gõ lại công thức cho rõ đi, khó đọc quá

\(ax+bx+ay+by\)

\(=x\left(a+b\right)+y\left(a+b\right)\)

\(=\left(x+y\right)\left(a+b\right)\)

\(xy+1-x-y\)

\(=x\left(y-1\right)-\left(y-1\right)\)

\(=\left(x-1\right)\left(y-1\right)\)

\(x^2-y^2-5x-5y\)

\(=\left(x+y\right)\left(x-y\right)-5\left(x+y\right)\)

\(=\left(x+y\right)\left(x-y-5\right)\)

1 ) \(x^2-x-y^2-y=\left(x^2-y^2\right)+\left(-x-y\right)=\left(x+y\right)\left(x-y\right)-\left(x+y\right)=\left(x+y\right)\left(x-y-1\right)\)

2 ) \(x^2-2xy+y^2-z^2=\left(x-y\right)^2-z^2=\left(x-y+z\right)\left(x-y-z\right)\)

3 ) \(5x-5y+ax-ay=5.\left(x-y\right)+a\left(x-y\right)=\left(x-y\right)\left(5+a\right)\)

4 ) \(a^3-a^2x-ay+xy=a^2.\left(a-x\right)-y.\left(a-x\right)=\left(a-x\right)\left(a^2-y\right)\)

5 ) \(xy.\left(x+y\right)+yz.\left(y+z\right)+xz.\left(x+z\right)+2xyz\)

\(=xy.\left(x+y\right)+y^2z+yz^2+x^2z+xz^2+xyz+xyz\)

\(=xy.\left(x+y\right)+\left(y^2z+xyz\right)+\left(yz^2+xz^2\right)+\left(x^2z+xyz\right)\)

\(=xy.\left(x+y\right)+yz.\left(x+y\right)+z^2.\left(x+y\right)+xz.\left(x+y\right)\)

\(=\left(x+y\right)\left(xy+yz+z^2+xz\right)=\left(x+y\right)\left[\left(xy+xz\right)+\left(yz+z^2\right)\right]\)

\(=\left(x+y\right)\left[x.\left(y+z\right)+z.\left(y+z\right)\right]=\left(x+y\right)\left(y+z\right)\left(x+z\right)\)

a Đề sai: )

b

\(a^3-a^2x-ay+xy\\ =a^2\left(a-x\right)-y\left(a-x\right)\\ =\left(a-x\right)\left(a^2-y\right)\)

c

\(4x^2-y^2+4x+1\\ =\left(2x\right)^2+2.2x.1+1-y^2\\ =\left(2x+1\right)^2-y^2\\ =\left(2x+1-y\right)\left(2x+1+y\right)\)

d

\(x^4+2x^3+x^2\\ =x^4+x^3+x^3+x^2\\ =x^3\left(x+1\right)+x^2\left(x+1\right)\\ =\left(x^3+x^2\right)\left(x+1\right)\)

e

\(5x^2-10xy+5y^2-5z^2\\ =5\left(x^2-2xy+y^2-z^2\right)\\ =5\left[\left(x-y\right)^2-z^2\right]\\ =5\left(x-y-z\right)\left(x-y+z\right)\)

c: =(2x+1)^2-y^2

=(2x+1+y)(2x+1-y)

d: =x^2(x^2+2x+1)

=x^2(x+1)^2

e: =5(x^2-2xy+y^2-z^2)

=5[(x-y)^2-z^2]

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

\(a,3x^2+2x=x\left(3x+2\right)\)

\(b,5x-5y+ax-ay=5\left(x-y\right)+a\left(x-y\right)=\left(x-y\right)\left(5+a\right)\)

\(c,4x^2-25=\left(2x-5\right)\left(2x+5\right)\)

\(d,x^2+6x+5=x^2+x+5x+5=x\left(x+1\right)+5\left(x+1\right)=\left(x+1\right)\left(x+5\right)\)

\(e,x^2-y^2+2y-1=x^2-\left(y^2-2y+1\right)=x^2-\left(y-1\right)^2=\left(x-y+1\right)\left(x+y-1\right)\)

a ) 3x² + 2x

= x. ( 3x + 2 )

b ) 5x - 5y + ax - ay

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

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

= ( 5 + a ) ( x - y ) 

c ) 4x² - 25

= ( 2x + 5 ) ( 2x - 5 )

d ) x² + 6x + 5

= x² + x + 5x + 5

= x.( x + 1 ) + 5.( x + 1 )

= ( x + 1 ) ( x + 5 )

e ) x² - y² + 2y - 1

= x² - ( y - 1 )²

= ( x - y + 1 ) ( x + y - 1 )

f ) x³ - 3x + 2

= x³ + 2x² - 2x² - 4x + x + 2

= x² ( x + 2 ) - 2x ( x + 2 ) + ( x + 2 )

= ( x + 2 ) ( x² - 2x + 1 )

= ( x + 2 ) ( x - 1 )²

\(a)\)\(3x^2+2x=x\left(3x-2\right)\)

\(b)\)\(5x-5y+ax-ay=5\left(x-y\right)+a\left(x-y\right)=\left(x-y\right)\left(a+5\right)\)

\(c)\)\(4x^2-25=\left(2x\right)^2-5^2=\left(2x-5\right)\left(2x+5\right)\)

\(d)\)\(x^2+6x+5=\left(x^2+x\right)+\left(5x+5\right)=x\left(x+1\right)+5\left(x+1\right)=\left(x+1\right)\left(x+5\right)\)

\(e)\)\(x^2-y^2+2y-1\)

\(=\)\(x^2-\left(y^2-2y+1\right)\)

\(=\)\(x^2-\left(y-1\right)^2\)

\(=\)\(\left(x-y+1\right)\left(x+y-1\right)\)

\(f)\)\(x^3-3x+2\)

\(=\)\(\left(x^3-x\right)-\left(2x-2\right)\)

\(=\)\(x\left(x^2-1\right)-2\left(x-1\right)\)

\(=\)\(x\left(x-1\right)\left(x+1\right)-2\left(x-1\right)\)

\(=\)\(\left(x-1\right)\left[x\left(x+1\right)-2\right]\)

\(=\)\(\left(x-1\right)\left(x^2+x-2\right)\)

Chúc bạn học tốt ~ 

a) \(x^2-x-y^2-y\)

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

\(=\left(x-y\right)\left(x+y\right)-\left(x+y\right)\)

\(=\left(x-y-1\right)\left(x+y\right)\)

b) \(x^2-2xy+y^2-z^2\)

\(=\left(x-y\right)^2-z^2\)

\(=\left(x-y-z\right)\left(x-y+z\right)\)

c) \(5x-5y+ax-ay\)

\(=5\left(x-y\right)+a\left(x-y\right)\)

\(=\left(5+a\right)\left(x-y\right)\)