数学化简求值 x平方-2x分之x平方-1除以(x-1- 2x-1分之x+1)

如果题目是：
(x² - 1)/(x² - 2x) ÷ [ x - 1 - (x+1)/(2x-1)] 则：
原式 =(x-1)(x+1)/[x(x-2)] ÷{ [(x-1)(2x-1)-(x+1)]/(2x-1) }
=(x-1)(x+1)/[x(x-2)] ÷ [2x(x-2)/(2x-1) ]
=(x-1)(x+1)/[x(x-2)] * (2x - 1) / [2x(x-2)]
= (x-1)(x+1)(2x-1)/[2x²(x-2)²]
把x = - 2 代入得：
原式=(-3)(-1)(-5)/(2*4*16)
=15/128