已知1/x-1/y=3,则5x+3y-5y/x-2xy-y的值
问题描述:
已知1/x-1/y=3,则5x+3y-5y/x-2xy-y的值
答
因为:1/x-1/y=3,所以:(y-x)/xy=3,则:y-x=3xy
所以:(5x+3xy-5y)/(x-2xy-y)=[5(x-y)+3xy]/[(x-y)-2xy]
=[-15xy+3xy]/[-3xy-2xy]=12/5