Simplify: z3−zz2+2z+1⋅z+1z−1\frac{z^3 - z}{z^2 + 2z + 1} \cdot \frac{z+1}{z-1}z2+2z+1z3−z⋅z−1z+1.
zzz
z−1z-1z−1
z+1z+1z+1
z(z−1)z+1\frac{z(z-1)}{z+1}z+1z(z−1)