题目

x^2y-x^3/x^2+2xy+y^2÷x/x-y乘以x+y/x^2-2xy+y^2

提问时间：2021-12-20

答案

原式=[-x^2(x-y)/(x+y)^2]×[(x-y)/x]×[(x+y)/(x-y)^2]
=-x^2(x-y)^2(x-y)/[x(x+y)^2(x-y)^2]
=-x/(x-y)