3 and 4 .Determinants and Matrices question bank (Mathematics)

Let $\omega \neq 1$ be a cube root of unity and $S$ be the set of all non-singular matrices of the form $\begin{bmatrix} 1 & a & b \\ \omega & 1 & c \\ \omega^2 & \omega & 1 \end{bmatrix}$ where each of $a$,$b$,and $c$ is either $\omega$ or $\omega^2$. Then,the number of distinct matrices in the set $S$ is

The value of $(1+\Delta)(1-\nabla)$ is