2.76 Determine for which values of $m$ one of the roots of the equation $z^{3}-\left(m^{2}-m+7\right) z-\left(3 m^{2}-3 m-6\right)=0$ is equal to -1. Find the two remaining roots of the equation for these values of $m$.
2.76 Assuming $z=-1$, we obtain the equation $m^{2}-m-6=0$ with respect to $m$, the roots of which are $m=3$ and $m=-2$. For each of these values of $m$, the given equation can be written as: $z^{3}-13 z-12=0$. This equation can be represented as $(z+1)(z+3)(z-4)=0$, from which $z_{1}=-1$; $z_{2}=-3 ; z_{3}=4$

Answer: $\quad z_{2}=-3, z_{3}=4$.