x4-x3-5x2-6x-4
问题描述：
x4-x3-5x2-6x-4
答
x^4-x^3-5x^2-6x-4
=-x(x^2+5x+6)+x^4-4
=[-x(x+2)(x+3)]+[(x^2+2)(x^-2)]