Đáp án:
$\text{Xin hay nhất ạ!}$
Giải thích các bước giải:
$\text{a/ $x^{5}$ - x³ + x² -1}$
$\text{=x³(x²-1)+(x²-1)}$
$\text{=(x³+1)(x²-1)}$
$\text{=(x+1)(x²-x+1)(x-1)(x+1)}$
$\text{=(x+1)²(x²-x+1)(x-1)}$
$\text{b/ a³-8+6a²-12a}$
$\text{=(a-2)(a²+2a+4)+6a(a-2)}$
$\text{=(a-2)(a²+2a+4+6a)}$
$\text{=(a-2)(a²+8a+4)}$
$\text{c/ $x^{4}$ + x³+x+1}$
$\text{= x³(x+1)+(x+1)}$
$\text{=(x³+1)(x+1)}$
$\text{=(x+1)(x²+x+1)(x+1)}$
$\text{=(x+1)²(x²+x+1)}$
$\text{d/ (a+b)³-(a-b)³}$
$\text{=(a+b-a+b)[(a+b)²+(a+b)(a-b)+(a-b)²]}$
$\text{= 2b[(a+b)²+(a²-b²)+(a-b)²]}$
