若x分之1减y分之1等于3,求x-2xy-y分之2x+3xy-2y

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若x分之1减y分之1等于3,求x-2xy-y分之2x+3xy-2y

若x分之1减y分之1等于3,求x-2xy-y分之2x+3xy-2y
若x分之1减y分之1等于3,求x-2xy-y分之2x+3xy-2y

若x分之1减y分之1等于3,求x-2xy-y分之2x+3xy-2y
(1/x)-(1/y)=3
===> (y-x)/(xy)=3
===> y-x=3xy
===> x-y=-3xy
所以,原式=[(x-y)-2xy]/[2(x-y)+3xy]
=(-3xy-2xy)/(-2*3xy+3xy)
=(-5xy)/(-3xy)
=5/3

1/x-1/y=3,所以(x-y)/xy=3 所以x-y=3xy
(2x+3xy-2y)/(x-2xy-y)=1+7xy/(x-2xy-y)=1+7xy/(3xy-2xy)=1+7=8