\det \left[ {\begin{array}{*{20}c}
 1 & 3 & 4 \\
 2 & 5 & {11} \\
 {13} & { - 2} & { - 6} \\
\end{array}} \right] = \sum\limits_{\sigma \in S_3 } {\left( { - 1} \right)^{I\left( \sigma \right)} \prod\limits_{i = 1}^3 {a_{i,\sigma \left( i \right)} } } =