$-52$

$\left(\begin{matrix}5&1&-1\\12&-1&2\\9&2&1\end{matrix}\right)$

$\left(\begin{matrix}\frac{5}{52}&\frac{3}{52}&-\frac{1}{52}\\-\frac{3}{26}&-\frac{7}{26}&\frac{11}{26}\\-\frac{33}{52}&\frac{1}{52}&\frac{17}{52}\end{matrix}\right)$

$5$

$\left(\begin{matrix}5&12&9\\1&-1&2\\-1&2&1\end{matrix}\right)$

$3,3$

$\left(\begin{matrix}1&0&0\\0&1&0\\0&0&1\end{matrix}\right)$

$\left[\begin{array}{rrr}-5 & -3 & 1 \\ 6 & 14 & -22 \\ 33 & -1 & -17\end{array}\right]$