(x^3+2x^2+x)/(x^3+x^2-x-1)
[x(x^2+2x+1)]/[x^2(x+1)-(x-1)]
[x(x+1)^2]/[(x+1)(x^2-1)]
[x(x+1)]/[(x-1)(x+1)]
x/(x-1)