化简代数式：（x的平方-2x/x的平方-1）/（x-1-2x-1/x+1)

原式=(x²-2)/(x+1)(x-1)÷[(x²-1-2x+1)/(x+1)
=(x²-2)/(x+1)(x-1)×(x+1)/(x²-2)
=1/(x-1)