题目

x-y/x²÷x²-2xy+y²/xy*（xy-x²）

提问时间：2021-01-23

答案

(x-y)/x²÷(x²-2xy+y²)/xy×(xy-x²)=(x-y)/x²÷(x+y)²/xy×x(y-x)=(x-y)²/x²×xy/(x+y)²×x(y-x)=-(x-y)³/(x+y)²