Question

Matriz e determinantes.
Questão na imagem abaixo.

Answer 1

$x= \left[\begin{array}{cc}1&0\\0&1\end{array}\right] . \left[\begin{array}{cc}1&0\\0&1\end{array}\right] + \left[\begin{array}{cc}3&1\\2&-1\end{array}\right] - \left[\begin{array}{cc}-1&0\\1&-2\end{array}\right] \\ \\ x= \left[\begin{array}{cc}(1.1+0.0)&(1.0+0.1)\\(0.1+1.0)&(1.0+0.1)\end{array}\right] + \left[\begin{array}{cc}(3+1)&(1-0)\\(2-1)&(-1+2)\end{array}\right]$
$x= \left[\begin{array}{cc}1&0\\0&0\end{array}\right] + \left[\begin{array}{cc}4&1\\1&1\end{array}\right] \\ \\ x= \left[\begin{array}{cc}(1+4)&(0+1)\\(0+1)&(0+1)\end{array}\right] \\ \boxed {x= \left[\begin{array}{cc}5&1\\1&1\end{array}\right]}$