（x²-1）÷x÷[1-(2x-1)÷（x-1）]
(2x-1)÷（x-1）=(2x-1)/(x-1)=[2(x-1)+1]/(x-1)=2+1/(x-1) ……①
[1-(2x-1)÷（x-1）]=[(x-1)-(2x-1)]/(x-1)=-x/(x-1)=x/(1-x)……②
x÷[1-(2x-1)÷（x-1）]=x/x/(1-x)=1-x……③
（x²-1）÷x÷[1-(2x-1)÷（x-1）]=（x²-1）/(1-x)=(x+1)(x-1)/(1-x)=-x-1……④
把x=2代入 -x-1 = -3
把x=2代入原式:(4-1)/2/(1-3/1)=-3
說明化簡正確
PS.可能看著有點(diǎn)亂 就是從右往左化簡
（x²-1）÷x÷[1-(2x-1)÷（x-1）]
先化簡(2x-1)÷（x-1）也就是①
然后1-(2x-1)÷（x-1）也就是②
接著是x÷[1-(2x-1)÷（x-1）] 也就是③
最后是全部的（x²-1）÷x÷[1-(2x-1)÷（x-1）] 也就是④