\(4a^2-4ab+b^2-9a^2b^2\)

\(=\left(2a-b\right)^2-9a^2b^2\)

\(=\left(2a-b-3ab\right)\left(2a-b+3ab\right)\)

\(7a^2-7ax-9a+9x=\left(7a^2-7ax\right)-\left(9a-9x\right)=7a\left(a-x\right)-9\left(a-x\right)=\left(a-x\right)\left(7a-9\right)\)

7a(a-x)-9(a-x)

(7a-9)(a-x)

\(7a^2-7ax-9a+9x=7a\left(a-x\right)-9\left(a-x\right)=\left(7a-9\right)\left(a-x\right)\)

\(A=b^4-9a^2-4b^2+4=b^4-4b^2+4-9a^2\)

\(=\left(b^2-2\right)^2-9a^2\)

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

\(A=b^4-9a^2-4b^2+4\)

\(A=\left(b^2\right)^2-2.2.b^2+2^2-9a^2\)

\(A=\left(b^2-2\right)^2-\left(3a\right)^2\)

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

_Hắc phong_

\(Â=b^4-9a^2-4b^2+4\)

     \(=b^4-4b^2+4-\left(3a\right)^2\)

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

bằng (3a-b)^2-1 

bằng (3a-b+1)(3a-b+1)

\(A=9a^2-6ab+b^2-1\)

\(A=\left(3a-b\right)^2-1\)

\(A=\left(3a-b-1\right)\left(3a-b+1\right)\)

P/s haphuong

Lời giải:
$B=(a^4+b^4-2a^2b^2)+c^4-2c^2(a^2-b^2)-4b^2c^2$

$=(a^2-b^2)^2+c^4-2c^2(a^2-b^2)-(2bc)^2$

$=(a^2-b^2-c^2)^2-(2bc)^2$
$=(a^2-b^2-c^2-2bc)(a^2-b^2-c^2+2bc)$

$=[a^2-(b+c)^2][a^2-(b-c)^2]$

$=(a-b-c)(a+b+c)(a-b+c)(a+b-c)$

Ý bạn ý là phân tích thành nhân tử đó.             

`a, x^3 + 4x = x(x^2+4)`

`b, 6ab - 9ab^2 = 3ab(2-b)`

`c, 2a(x-1) + 3b(1-x)`

`= (2a-3b)(x-1)`

`d, (x-y)^2 - x(y-x)`

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

`= (2x-y)(x-y)`