Question

已知1/x-1/y=3，求(5x+xy-5y)/(x-xy-y)的值

要详细过程，大概是因式分解

Answer 1

1/x-1/y=(y-x)/xy=3
y-x=3xy
x-y=-3xy

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

Answer 2

1/x-1/y=(y-x)/xy=3
y-x=3xy
x-y=-3xy

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