Solution (source code)

= Solution

Write $-8=8e^{i(\pi+2\pi k)}$. Its cube roots have <modulus> two and <arguments> $(\pi+2\pi k)/3$, for $k=0,1,2$. Thus
$$
\boxed{1+i\sqrt3,\qquad -2,\qquad 1-i\sqrt3.}
$$
Each cube equals $-8$, and a cubic <polynomial> has no further distinct roots.