(-x-2y)(x2-2xy+4y2)等于多少
问题描述:
(-x-2y)(x2-2xy+4y2)等于多少
答
(-x-2y)(x2-2xy+4y2)
=-(x+2y)*(x2-2xy+4y2)
=-x^3-(2y)^3
=-x^3-8y^3