Find y, if \(\begin{pmatrix}5 & -6 \\2 & -7\end{pmatrix}\begin{pmatrix}x \\ y \end{pmatrix} = \begin{pmatrix}7 \\-11\end{pmatrix}\)
If \(\begin{vmatrix}-x & 12 \\-1 & 4 \end{vmatrix} = - 12\), find x.
