先化简,再求值.[(2/x+1)+(4/x方-1)]÷x/x-1x=2、

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先化简,再求值.
[(2/x+1)+(4/x方-1)]÷x/x-1
x=2、

[2/(x+1)+4/(x²-1)]÷x/(x-1)
=[(2/(x+1)+4/(x-1)(x+1)]÷x/(x-1)
=[2(x-1)/(x+1)(x-1)+4/(x-1)(x+1)]÷x/(x-1)
=[2(x-1)+4/(x-1)(x+1)]÷x/(x-1)
=[2(x+1)/(x-1)(x+1)]÷x/(x-1)
=[2/(x-1)]÷x/(x-1)
=[2/(x-1)]×(x-1)/x
=2/x
当x=2时
上式=1