Question

determine a matriz inversa de cada uma das  matrizes:

a)  5  3
     3  2

b) 3  8
    2  5

Answer 1

$A) \left[\begin{array}{cc}5&3\\3&2\end{array}\right] \\ det=10-9 \\ det=1 \\ \\ \left[\begin{array}{cc}2&-3\\-3&5\end{array}\right]$

$B) \left[\begin{array}{cc}3&8\\2&5\end{array}\right] \\ det=15-16 \\ det=-1 \\ \\ \left[\begin{array}{cc} \frac{5}{-1} & \frac{-8}{-1} \\ \frac{-2}{-1} & \frac{3}{-1} \end{array}\right] \\ \\ \left[\begin{array}{cc}-5&8\\2&-3\end{array}\right]$