Solution (source code)

= Solution

The matrix of <cofactors> is $\begin{pmatrix}-1&2&-3\\2&0&-2\\-3&-2&3\end{pmatrix}$. Transposing and dividing by the nonzero <determinant> gives the <inverse matrix>
$$
\boxed{S^{-1}=\begin{pmatrix}1/4&-1/2&3/4\\-1/2&0&1/2\\3/4&1/2&-3/4\end{pmatrix}.}
$$
Multiplication by $S$ verifies the <identity matrix>.