Resposta:

a)

[tex]A=\left[\begin{array}{ccc}-1&2\\5&4\\\end{array}\right]\\B=\left[\begin{array}{ccc}6&7\\-3&0\\\end{array}\right]\\C=\left[\begin{array}{ccc}1&1\\1&1\\\end{array}\right]\\0_{2X2}=\left[\begin{array}{ccc}0&0\\0&0\\\end{array}\right] \\[/tex]

[tex]a)\\\left[\begin{array}{ccc}-1&2\\5&4\\\end{array}\right] +\left[\begin{array}{ccc}6&7\\-3&0\\\end{array}\right] =\left[\begin{array}{ccc}5&9\\2&4\\\end{array}\right]\\\left[\begin{array}{ccc}6&7\\-3&0\\\end{array}\right]+\left[\begin{array}{ccc}-1&2\\5&4\\\end{array}\right]=\left[\begin{array}{ccc}5&9\\2&4\\\end{array}\right]\\[/tex]

[tex]b)\\\left[\begin{array}{ccc}-1&2\\5&4\\\end{array}\right]+(\left[\begin{array}{ccc}6&7\\-3&0\\\end{array}\right]+\left[\begin{array}{ccc}1&1\\1&1\\\end{array}\right])=\left[\begin{array}{ccc}6&10\\3&5\\\end{array}\right]\\(\left[\begin{array}{ccc}-1&2\\5&4\\\end{array}\right]+\left[\begin{array}{ccc}6&7\\-3&0\\\end{array}\right])+\left[\begin{array}{ccc}1&1\\1&1\\\end{array}\right]=\left[\begin{array}{ccc}6&10\\3&5\\\end{array}\right][/tex]

[tex]c)\\\left[\begin{array}{ccc}6&6\\-3&0\\\end{array}\right] +\left[\begin{array}{ccc}0&0\\0&0\\\end{array}\right]=\left[\begin{array}{ccc}6&6\\-3&0\\\end{array}\right][/tex]

[tex]d)\\\left[\begin{array}{ccc}1&1\\1&1\\\end{array}\right]+\left[\begin{array}{ccc}-1&-1\\-1&-1\\\end{array}\right]=\left[\begin{array}{ccc}0&0\\0&0\\\end{array}\right][/tex]

Eh isso, um beijo da anitta