因式分解x⁴-x³-3x²+x+2
问题描述：
因式分解x⁴-x³-3x²+x+2
答
=x^3 (x-1) + (x-1)(-3x-2)
= (x-1)(x^3 - 3x - 2)
= (x-1)(x-1)(x^2 +x +2)