$\left(\begin{matrix}1&3&5&2\\0&-1&3&4\\2&1&9&6\\3&2&4&8\end{matrix}\right)$

$160$

$\left(\begin{matrix}-\frac{23}{40}&-\frac{17}{20}&\frac{21}{40}&\frac{7}{40}\\\frac{7}{16}&\frac{1}{8}&-\frac{5}{16}&\frac{1}{16}\\\frac{1}{80}&-\frac{1}{40}&\frac{13}{80}&-\frac{9}{80}\\\frac{1}{10}&\frac{3}{10}&-\frac{1}{5}&\frac{1}{10}\end{matrix}\right)$

$17$

$\left(\begin{matrix}1&0&2&3\\3&-1&1&2\\5&3&9&4\\2&4&6&8\end{matrix}\right)$

$4,4$

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