已知1/x-1/y=2,求5x+3xy-5y/x-2xy-y

问题描述:

已知1/x-1/y=2,求5x+3xy-5y/x-2xy-y

1/x-1/y=2
(y-x)/xy=2
y-x=2xy
5x+3xy-5y/x-2xy-y
=[5(x-y)+3xy]/[(x-y)-2xy]
=(-10xy+3xy)/(-2xy-2xy)
=7/4