已知1/x-1/y=5,求分式3x+5xy-3y/x-3xy-y的值.

问题描述:

已知1/x-1/y=5,求分式3x+5xy-3y/x-3xy-y的值.
1个回答 分类:数学 2014-12-02

问题解答:

我来补答
1/x-1/y=5
(y-x)/xy=5
y-x=5xy
x-y=-5xy
3x+5xy-3y/x-3xy-y
=3(x-y)+5xy/(x-y)-3xy
=3*(-5xy)+5xy/-5xy-3xy
=-10xy/-8xy
=5/4
 
 
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