One more determinant related question.

Alright, here is another question that I need some help with, I think I have an idea of how to do it but it never hurts to make sure, though

The question states:

solve the following equation.

$\displaystyle

\begin{vmatrix}

0 & 0 & -1\\

3 & x & 0\\

2 & 0 & 3

\end{vmatrix}=x^2

$

My idea is to either, expand by minors, or, to evaluate it by using the main diagonals(?) method.

Which way would be quickest and easiest to do?

Or am I headed in the wrong direction entirely?