（x+y分之y）-（y²-x²分之xy)

分类: 作业答案 • 2021-12-03 13:48:01

问题描述：

答

=y/(x+y)+xy/(x+y)(x-y)
=[y(x-y)+xy]/(x+y)(x-y)
=(2xy-y²)/(x²-y²)