因式分解:(x+2y)的"立方"-x-2y

问题描述:

因式分解:(x+2y)的"立方"-x-2y

(x + 2y)^3 - x - 2y
=(x + 2y)^3 - (x + 2y)
=(x + 2y)^2(x + 2y) - (x + 2y)
=(x + 2y)[(x + 2y)^2 - 1]
=(x + 2y)(x + 2y + 1)(x + 2y - 1)