(1)已知1/X-1/Y=3,求分式(2X+3XY-2Y)/(X-2XY-Y)的值.(2)化简:(x的二次方-2xy+y的二次方-1)/(x-y-1)=

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(1)已知1/X-1/Y=3,求分式(2X+3XY-2Y)/(X-2XY-Y)的值.(2)化简:(x的二次方-2xy+y的二次方-1)/(x-y-1)=

(1)已知1/X-1/Y=3,求分式(2X+3XY-2Y)/(X-2XY-Y)的值.(2)化简:(x的二次方-2xy+y的二次方-1)/(x-y-1)=
(1)已知1/X-1/Y=3,求分式(2X+3XY-2Y)/(X-2XY-Y)的值.
(2)化简:(x的二次方-2xy+y的二次方-1)/(x-y-1)=

(1)已知1/X-1/Y=3,求分式(2X+3XY-2Y)/(X-2XY-Y)的值.(2)化简:(x的二次方-2xy+y的二次方-1)/(x-y-1)=
(1)∵1/X-1/Y=3∴y-x=3xy
分式(2X+3XY-2Y)/(X-2XY-Y)=[-2﹙y-x﹚+3XY]/[-﹙y-x﹚-2XY]
=﹙-6XY+3XY﹚/﹙-3xy-2xy﹚
=﹙-3xy﹚/﹙-5xy﹚
=3/5
(2):(x的二次方-2xy+y的二次方-1)/(x-y-1)=﹙x²-2xy+y²-1﹚/﹙x-y-1﹚
=[﹙x-y﹚²-1]/﹙x-y-1﹚
=[﹙x-y+1﹚﹙x-y-1﹚]/﹙x-y-1﹚
=x-y+1

那么简单 别拿出来卡 变形 就可以

1、1/X-1/Y=3 可得 x-y=-3xy
(2X+3XY-2Y)/(X-2XY-Y)=(3xy-6xy)/(-3xy-2xy)=3/5
2、(x^2-2xy+y^2-1)/(x-y-1)=[(x-y)^2-1]/(x-y-1)
=(x-y+1)(x-y-1)/(x-y-1)
=x-y+1