Câu hỏi của Mạnh Nguyễn

Question

1.Phân tích thành nhân tử

a)$x^2\left(x-1\right)-4x^2+8x-4$

b)$x^3+27+\left(x+3\right)\left(x-9\right)$

Nhiên An Trần · Accepted Answer

a, $x^2\left(x-1\right)-4x^2+8x-4$

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

$=x^2\left(x-1\right)-4\left(x-1\right)^2$

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

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

b, $x^3+27+\left(x+3\right)\left(x-9\right)$

$=\left(x+3\right)\left(x^2-3x+9\right)+\left(x+3\right)\left(x-9\right)$

$=\left(x+3\right)\left(x^2-3x+9+x-9\right)$

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

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

Sai thì nhớ báo nhéCâu trả lời: a, $x^2\left(x-1\right)-4x^2+8x-4$