UC知道初一分式求值
来源：百度知道 编辑：UC知道 时间：2024/06/20 07:42:28
已知1/x-1/y=3,求分式：(2x+3xy-2y)/(x-2xy-y)的值，要过程！过程！
1/x-1/y=3,
(y-x)/xy=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
将1/X-1/Y=3 同乘XY 得Y-X=3XY 则X-Y=-3XY 则(2X+3XY-2Y)/(X-2XY-Y)=(3XY-3XY)/(-2XY-3XY)=0
由1/x-1/y=3可以推出(y-x)/xy=3
得(y-x)=3xy
把(y-x)=3xy代入(2x+3xy-2y)/(x-2xy-y)得
(2x+3xy-2y)/(x-2xy-y)
=[2(x-y)+3xy]/(x-y-2xy)
=(-6xy+3xy)/(-3xy-2xy)
=(-3xy)/(-5xy)
=3/5
1/x-1/y=3推出-3xy=x-y
(2x+3xy-2y)/(x-2xy-y)=[2(x-y)+3xy]/[x-y-2xy]=-3xy/-5xy=3/5
1/x-1/y=3,
(y-x)/xy=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
1/x-1/y=3推出-3xy=x-y
(2x+3xy-2y)/(x-2xy-y)=[2(x-y)+3xy]/[x-y-2xy]=-3xy/-5xy=3/5