Here is the portion of my code that is rather bothersome:
\begin{center}
\begin{matrix}
E_1 \\
E_2
\end{matrix}
\begin{bmatrix}
1 & h & 2 \\
-5 & 15 & -12
\end{bmatrix}
\end{center}
And the result is

How do I go about getting the E_1 E_2 column to the left of the bmatrix?
\matrixcommand? – Werner Jan 25 '14 at 17:24\[\]and delete the blank line – David Carlisle Jan 25 '14 at 17:24