😄 具体的给好评 最好是照片

😄 具体的给好评 最好是照片
 

∵1/x-1/y=3
∴y-x=3xy
x-y=-3xy
2x+3xy-2y/x-2xy-y
=[2(x-y)+3xy]/[(x-y)-2xy]
=(-6xy+3xy)/(-3xy-2xy)
=-3xy/(-5xy)
=3/5