Solve. z to the third power -1=0
$\displaystyle z^3 = 1$
z can be any of three roots of unity: $\displaystyle 1$, $\displaystyle e^{i \frac{2\pi}{3}}$, and $\displaystyle e^{i \frac{4\pi}{3}}$ (which correspond to three evenly spaced points on the unit circle).