x-y分之2-(x-y)平方分之x+y 计算

题目

x-y分之2-(x-y)平方分之x+y 计算

答案

2/(x-y)-(x+y)/(x-y)^2
={2(x-y)-(x+y)}/(x-y)^2
=(x-3y)/(x-y)^2