若1/x-1/y等于3,求(2x+3xy-2y)/(x+2xy-y)的值

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若1/x-1/y等于3,求(2x+3xy-2y)/(x+2xy-y)的值
若1/x-1/y等于3,求(2x+3xy-2y)/(x+2xy-y)的值

若1/x-1/y等于3,求(2x+3xy-2y)/(x+2xy-y)的值
1/x-1/y=3
(y-x)/xy=3
y-x=3xy
即x-y=-3xy
(2x+3xy-2y)/(x+2xy-y)
[2(x-y)+3xy]/[(x-y)+2xy]
=(-6xy+3xy)/(-3xy+2xy) (注:把x-y=-3xy代入得)
=3