x^4+3x^3-6x-4
问题描述：
x^4+3x^3-6x-4
答
原式=x^4+2x³+x³+2x²-2x²-6x-4
=x²(x+2)+x²(x+2)-2(x²+3x+2)
=x²(x+2)+x²(x+2)-2(x+1)(x+2)
=(x+2)(x³+x²-2x-2)
=(x+2)[x²(x+1)-2(x+1)]
=(x+2)(x+1)(x²-2)