Question

一道数学计算题，不知道为什么我就是算不出来。。。。急求大家帮忙，要具体过程，谢谢！

Answer 1

x^2-x-1=0
x^2-1=x
[3x/(x^2-1)-x/(x-1)]/(x-2)=[3x/x-(x^2-1)/(x-1)]/(x-2)=[3-(x+1)(x-1)/(x-1)]/(x-2)=(3-x-1)/(x-2)=(2-x)/(x-2)=-1

Answer 2

x^2-x-1=0
所以x^2-1=x;
那么原式=（3*x/x-(x^2-1)/(x-1))/(x-2)
=(3-(x+1)(x-1)/(x-1))/(x-2)
=(3-x-1)/(x-2)
=(2-x)/(x-2)
=-1

Answer 3

题目要求：先化简，再求值。所以上面两位的解答不合题意。
（1）化简：[3x/(x^2-1)-x/(x-1)]÷(x-2)
=[3x/(x^2-1)-x(x+1)/(x-1)(x+1)]÷(x-2)
=[3x-x(x+1)]/(x^2-1)÷(x-2)
=x(2-x)/(x^2-1)÷(x-2)
=- x/(x^2-1)
（2）求值：由x^2-x-1=0得x^2-1=x
∴原式=- x/(x^2-1)=-1

Answer 4

我是来拿分的