已知x-y=3xy,求2x-3xy-2y/x-2xy-y
问题描述：
已知x-y=3xy,求2x-3xy-2y/x-2xy-y
答
(2x-3xy-2y)/(x-2xy-y)
=[2(x-y)-3xy]/[(x-y)-2xy]
=(2×3xy-3xy)/(3xy-2xy)
=(3xy)/(xy)
=3