已知xy/(x+y)=2求(3x-5y+3y)/(-x+3xy-y)
问题描述：
已知xy/(x+y)=2求(3x-5y+3y)/(-x+3xy-y)
答
化简已知条件得：xy=2(x+y)
代入算式,得：（3(x+y)-10(x+Y))/(6(x+Y)-(x+y))＝-7/5.
注：算式中的5Y应为5XY吧