(Có x là nhân tử chung)

= x(x2 + 2xy + y2 – 9)

(Có x2 + 2xy + y2 là hằng đẳng thức)

= x[(x2 + 2xy + y2) – 9]

= x[(x + y)2 – 32]

(Xuất hiện hằng đẳng thức (3)]

= x(x + y – 3)(x + y + 3)

Hok tốt

Phần b đây nha

x2x2 – 2xy + y2y2 - z2z2

      = (x2x2 – 2xy + y2y2) – z2z2

      = (x−y)2x-y2 – z2z2

      = (x – y + z)(x – y – z)

Hok tốt

TL

a) x³-2x²+x-xy²

=x(x²-2x+1-y²)

=x[(x-1)²-y²]

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

K mik nha 

HT

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) \(x^2-xy+x-y\)

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

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

b) \(x^2+5x+6\)

\(=x^2+2x+3x+6\)

\(=x\left(x+2\right)+3\left(x+2\right)\)

\(=\left(x+3\right)\left(x+2\right)\)

\(2xy-x^2-y^2+16\)

\(=16-\left(x-y\right)^2\)

\(=\left(4-x+y\right)\left(4+x-y\right)\)

x^2-2xy+y^2-z^2

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

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

5x-5y+5x-ay

xy(x+y)+yz(y+z)+xz(x+z)+2xyz

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

b: \(=-xy^2\cdot x^2-xy^2\cdot z=-xy^2\left(x^2+z\right)\)

c: x^2y^3-xy^2

=xy^2*xy-xy^2

=xy^2(xy-1)

d: -x^3z-z

=z(-x^3-1)

=-z(x+1)(x^2-x+1)

e: =x(x-y)+(x-y)

=(x-y)(x+1)

n: =x^2(x-1)-(x-1)

=(x-1)(x^2-1)

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

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

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

2)\(5x-5y+ax-ay=5\left(x-y\right)+a\left(x-y\right)=\left(x-y\right)\left(a+5\right)\)

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