问题描述: 若1/x-1/y=3,则2x+3xy-2y/x-y-2xy的值是多少? 1个回答 分类:数学 2014-10-30 问题解答: 我来补答 1/x-1/y=3(y-x)/(xy)=3y-x=3xyx-y=-3xy(2x+3xy-2y)/(x-y-2xy)=[2(x-y)+3xy]/[(x-y)-2xy]=(-6xy+3xy)/(-3xy-2xy)=(-3xy)/(-5xy)=3/5 展开全文阅读