已知1除X-1除Y=3,求分式2X+3XY-2Y/X-2XY-Y

1/x-1/y=3
通分
(y-x)/xy=3
y-x=3xy
所以x-y=-3xy
原式=[2(x-y)+3xy]/[(x-y)-2xy]
=[2(-3xy)+3xy]/[(-3xy)-2xy]
=(-3xy)/(-5xy)
=3/5