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