(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

a/ x^3-6x^2+12x-8

=(x-2)^3

b/x^2+5x+4

=x^2+x+4x+4

=x(x+1)+4(x+1)

=(x+1)(x+4)

c/ 16^2-9(x+1)^2=0

<=> (4x-3x-3)(4x+3x+3)=0

<=>x-3=0 hay 7x+3=0

<=> x=3 hay x=-3/7

d/ x^3-2x^2-x+2

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

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

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

e/x^2+y^2-2xy-x+y

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

f/x^3+y^3+3y^2+3y+1

=x^3+(y+1)^3

=(x+y+1)[x^2-xy-x+(y+1)^2]

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

b. x²+2.5/2x+(5/2)²-(5/2)²+4

= (x+5/2)²-25/4+4

=(x+5/2)²-(3/2)²

= x+ 5/2 -3/2 ) . (x+5/2-3/2)

= (x+1 ) (x+2)

c. 

(4x)²- [3(x+1)]² =0

[4x-3(x+1)] [4x+3(x+1)] =0

(x-3) (7x+3) =0

<=> x-3 =0 => x = 3

7x+3=0 => x= -3/7

d. x³-2x²-x+2

= (x³-2x²) - (x+2) 

= x² (x-2) - (x-2)

= (x-2) (x²-1)

CHÚC BẠN HỌC TỐT 

* Tớ còn a, e, và f sorry nó k dễ để suy nghĩ trong thơi gian ngắn được nên tớ bỏ !! Ahihihih

#Đào lê anh thư : bạn ơi câu e cậu còn thiếu thì phở ???

a) Ta có :\(x^3-3.x^2.2+3.x+2^2+2^3\)(Hằng đẳng thức số 5 đấy bạn)

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

b) Ta có:\(x^2+5x+4=x^2+4x+1x+4\)

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

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

c) Ta có :\(16x^2-9\left(x+1\right)^2=0\)

\(\left[4x+3\left(x+1\right)\right].\left[4x-3\left(x+1\right)\right]=0\)(Hằng đẩng thức số 3)

\(\left(4x+3x+3\right).\left(4x-3x-3\right)=0\)

 \(7x+3.\left(x-3\right)=0\)

\(\Rightarrow7x+3=0\)hoặc \(x-3=0\)

\(\Rightarrow7x=-3\)    hoặc \(x=0+3\)

\(\Rightarrow x=\frac{-3}{7}\)      hoặc \(x=3\)

Vậy:\(x=\frac{-3}{7};3\)

d) Ta có \(x^3-2x^2-x+2\)

\(=\left(x^3-x\right)-\left(2x^2-2\right)\)
\(=x\left(x^2-1\right)-2\left(x^2-1\right)\)

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

Bây giờ hơi trễ rồi để mai mình làm tiếp 2 câu cuối nhá.

Rất vui khi được giúp bạn !!1 : =))

c: \(\left(x+y\right)^3-x^3-y^3\)

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

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

\(=3xy\left(x+y\right)\)

a) \(4x\left(a-b\right)+6xy\left(b-a\right)\)

\(=4x\left(a-b\right)-6xy\left(a-b\right)\)

\(=\left(4x-6xy\right)\left(a-b\right)\)

\(=2x\left(2-3y\right)\left(a-b\right)\)

b) \(\left(6x+3\right)-\left(2x-5\right)\left(2x+1\right)\)

\(=3\left(2x+1\right)-\left(2x-5\right)\left(2x+1\right)\)

\(=\left(3-2x+5\right)\left(2x+1\right)\)

\(=\left(8-2x\right)\left(2x+1\right)\)

\(=2\left(4-x\right)\left(2x+1\right)\)

g: \(\left(3x-1\right)^2-\left(x+3\right)^2\)

\(=\left(3x-1-x-3\right)\left(3x-1+x+3\right)\)

\(=\left(2x-4\right)\left(4x+2\right)\)

\(=4\left(x-2\right)\left(2x+1\right)\)

a) x³-2x²-x+2

=x(x²-1)+2(-x²+1)

=x(x²-1)-2(x²-1)

=(x²-1)(x-2)

b)

x²+6x-y²+9

=x²+6x+9-y²

=(x+3)²-y²

^{=(x+3-y)(x+3+y)}

a) 3x³ + 6x²y

= 3x².(x + 2y)

b) 2x³ - 6x²

= 2x².(x - 2)

c) 18x² - 20xy

= 2x.(9x - 10y)

d) xy + y² - x - y

= (xy + y²) - (x + y)

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

= (x + y)(y - 1)

e) (x²y² - 8)² - 1

= (x²y² - 8 - 1)(x²y² - 8 + 1)

= (x²y² - 9)(x²y² - 7)

= (xy - 3)(xy + 3)(x²y² - 7)

f) x² - 7x - 8

= x² - 8x + x - 8

= (x² - 8x) + (x - 8)

= x(x - 8) + (x - 8)

= (x - 8)(x + 1)

a: \(3x^3+6x^2y\)

\(=3x^2\cdot x+3x^2\cdot2y=3x^2\left(x+2y\right)\)

b: \(2x^3-6x^2=2x^2\cdot x-2x^2\cdot3=2x^2\left(x-3\right)\)

c: \(18x^2-20xy=2x\cdot9x-2x\cdot10y=2x\left(9x-10y\right)\)

d: \(xy+y^2-x-y\)

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

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

e: \(\left(x^2y^2-8\right)^2-1\)

\(=\left(x^2y^2-8-1\right)\left(x^2y^2-8+1\right)\)

\(=\left(x^2y^2-7\right)\left(x^2y^2-9\right)\)

\(=\left(x^2y^2-7\right)\left(xy-3\right)\left(xy+3\right)\)

f: \(x^2-7x-8\)

\(=x^2-8x+x-8\)

\(=x\left(x-8\right)+\left(x-8\right)=\left(x-8\right)\left(x+1\right)\)

g: \(10x^2\left(2x-y\right)+6xy\left(y-2x\right)\)

\(=2x\cdot\left(2x-y\right)\cdot5x-2x\cdot\left(2x-y\right)\cdot3y\)

\(=2x\left(2x-y\right)\left(5x-3y\right)\)

h: \(x^2-2x+1-y^2\)

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

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

i: \(2x\left(x+2\right)+x^2\left(-x-2\right)\)

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

k: \(-x^2+6x-9=-\left(x^2-6x+9\right)\)

\(=-\left(x^2-2\cdot x\cdot3+3^2\right)=-\left(x-3\right)^2\)

l: \(-2x^2+8xy-8y^2\)

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

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

m: \(3x^2+5x-3y^2-5y\)

\(=3\left(x^2-y^2\right)+5\left(x-y\right)\)

\(=3\left(x-y\right)\left(x+y\right)+5\left(x-y\right)\)

\(=\left(x-y\right)\left(3x+3y+5\right)\)

g) 10x²(2x - y) + 6xy(y - 2x)

= 10x²(2x - y) - 6xy(2x - y)

= 2x(2x - y)(5x - 3y)

h) x² - 2x + 1 - y²

= (x² - 2x + 1) - y²

= (x - 1)² - y²

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

i) 2x(x + 2) + x² (-x - 2)

= 2x(x + 2) - x²(x + 2)

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

k) -9 + 6x - x²

= -(x² - 6x + 9)

= -(x - 3)²

l) 8xy - 2x² - 8y²

= -2(x² - 4xy + 4y²)

= -2(x - 2y)²

m) 3x² + 5x - 3y² - 5y

= (3x² - 3y²) + (5x - 5y)

= 3(x² - y²) + 5(x - y)

= 3(x - y)(x + y) + 5(x - y)

= (x - y)[3(x + y) + 5]

= (x - y)(3x + 3y + 5)