((x+2y)(x-2y)+4(x-y)的2次)/6x

问题描述:

((x+2y)(x-2y)+4(x-y)的2次)/6x

((x+2y)(x-2y)+4(x-y)^2)/6x
=[(x^2-4y^2)+(4x^2-8xy+4y^2)]/6x
=(5x^2-8xy)/6x
=(5x-8y)/6