(x²-2x+1分之x²-1+x+1分之1-x)÷x-1分之x
=[(x-1)(x+1)/(x-1)² -(x-1)/(x+1)]×(x-1)/x
=[(x+1)/(x-1) -(x-1)/(x+1)]×(x-1)/x
=[(x+1)²-(x-1)²]/(x-1)(x+1)×(x-1)/x
=(x²+2x+1-x²+2x-1)/x(x+1)
=4x/x(x+1)
=4/(x+1)