Look at this matrix. Is it invertible? If so, try compute the inverse.

$$ A = \begin{bmatrix} 4 & 7 & 4 \\ 1 & 1 & 2 \\ 5 & 7 & 7 \end{bmatrix} $$
$$ A^{-1}=\begin{bmatrix} -7 & -21 & 10 \\ 3 & 8 & -4 \\ 2 & 7 & -3 \end{bmatrix} $$

© 2014 Emanuele Santoro