已知2/x-1/y=3,则(2y-x+4xy)/(3x-6y-5xy)=?

问题描述:

已知2/x-1/y=3,则(2y-x+4xy)/(3x-6y-5xy)=?

2/x-1/y=3
2y-x=3xy
(2y-x+4xy)/(3x-6y-5xy)
=[(2y-x)+4xy]/(-3(2y-x)-5xy]
=(3xy+4xy)/(-9xy-5xy)
=7xy/(-14xy)
=-1/2