10. Find the $6 \times 6$ enciphering matrix corresponding to the product cipher obtained by first using the Hill cipher with enciphering matrix $\left(\begin{array}{ll}3 & 1 \\ 2 & 1\end{array}\right)$, followed by using the Hill cipher with enciphering matrix $\left(\begin{array}{lll}1 & 1 & 0 \\ 1 & 0 & 1 \\ 0 & 1 & 1\end{array}\right)$.
$10 .\left(\begin{array}{llllll}5 & 2 & 0 & 0 & 0 & 0 \\ 3 & 1 & 3 & 1 & 0 & 0 \\ 2 & 1 & 3 & 1 & 0 & 0 \\ 0 & 0 & 2 & 1 & 3 & 1 \\ 0 & 0 & 2 & 1 & 2 & 1 \\ 0 & 0 & 0 & 0 & 5 & 2\end{array}\right)$