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Hello, I'm writing a text explaining the minors method on matrices, my code for matrices is something like this:


\begin{empheq}{align*}
\left|\begin{array}{ccc} 3&-2&1\\ -2&-4&-1\\ 2&-1&5 \end{array}\right|
\end{empheq}


I want to get this:
http://img856.imageshack.us/img856/6241/strikez.jpg ...