[(x^2-2x/x-1)*(1/x^3+X^2+x)除以x^2-1/x^2+x+1]除以(1-1/x-1)
=x(x-2)/(x-1)*[1/x(x^2+x+1)]*(x^2+x+1)/(x^2-1)*(x-1)/(x-2)
分子上有x(x-2),1,x^2+x+1 ,x-1 分母上有x-1,x(x^2+x+1)x^2-1 x-2
约分后=1/(x^2-1)
[(x^2-2x/x-1)*(1/x^3+X^2+x)除以x^2-1/x^2+x+1]除以(1-1/x-1)
=x(x-2)/(x-1)*[1/x(x^2+x+1)]*(x^2+x+1)/(x^2-1)*(x-1)/(x-2)
分子上有x(x-2),1,x^2+x+1 ,x-1 分母上有x-1,x(x^2+x+1)x^2-1 x-2
约分后=1/(x^2-1)