2x+2y分之x-y与的平方分之xy怎么通分 解: 第二个分母是x^2-y^2吧? 最简公分母是2(x+y)(x-y) 所以(x-y)/(2x+2y)=(x-y)^2/2(x+y)(x-y) xy/(x^2-y^2)=2xy/2(x+y)(x-y)