当2x-y\x+y=3时,求代数式2x-y/2x+2y+x+y/6x-3y的値.

问题描述:

当2x-y\x+y=3时,求代数式2x-y/2x+2y+x+y/6x-3y的値.
1个回答 分类:数学 2014-10-02

问题解答:

我来补答
2x-y\x+y=3
2x-y=3(x+y)
2x-y=3x+3y
3x-2x=-y-3y
x=-4y

2x-y/2x+2y+x+y/6x-3y
=(-8y-y)/(-8y+2y)+(-4y+y)/(-24y-3y)
=3/2+1/9
=29/18
 
 
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