约分 题目-(x+y)(x-y)^2 /(y+x)(y^2-x^2)

问题描述:

约分 题目
-(x+y)(x-y)^2 /(y+x)(y^2-x^2)

X-Y

-(x+y)(x-y)^2 /(y+x)(y^2-x^2)
=(x-y)^2/(x-y)(x+y)
=(x-y)/(x+y)