Resposta:
1- [tex]\left[\begin{array}{ccc}-1&-4&-7\\1&-2&-5\\3&0&-3\end{array}\right][/tex]
2- a) [tex]\left[\begin{array}{ccc}1&14\\5&-16\end{array}\right][/tex]
b) [tex]\left[\begin{array}{ccc}5&0\\-12&-2\end{array}\right][/tex]
3- a) [tex]\left[\begin{array}{ccc}2&5\\0&-3\end{array}\right][/tex]
b) [tex]\left[\begin{array}{ccc}92&60\\104&64\end{array}\right][/tex]
4- [tex]\left[\begin{array}{ccc}2&-1\\-5&3\end{array}\right][/tex]
