Solve for $X$ in matrix equation How can I solve for $X$ in this matrix equation?
$$\begin{bmatrix}-3&-8\\-9&5\end{bmatrix} X + \begin{bmatrix}4&-7\\3&-2\end{bmatrix} = \begin{bmatrix}5&8\\-1&-1\end{bmatrix} X$$
First I tried $AX + B = CX$ but then I don't know how to solve for $X$ because no matter what I do I end up getting rid of the $X$. 

Write the matrix equation in the form
$$A X = B$$
where $X, A, B \in \mathbb{R}^{2 \times 2}$. Vectorizing, one obtains a linear system of $4$ equations in $4$ unknowns
$$(I_2 \otimes A) \, \mbox{vec} (X) = \mbox{vec} (B)$$
Lastly, use Gaussian elimination.
