问题描述: 已知1/x-1/y=2,求3x+5xy-3y/x-xy-y 1个回答 分类:数学 2014-11-14 问题解答: 我来补答 将1/x-1/y=2通分可得:y-x=2xy,那么x-y=-2xy分子3x+5xy-3y=3*(x-y)+5xy=3*(-2xy)+5xy=-xy分母x-xy-y=(x-y)-xy=-2xy-xy=-3xy所以3x+5xy-3y/x-xy-y=-xy/-3xy=1/3 展开全文阅读