I think I was handed a trick question.

For the matrix $\displaystyle \left(\begin{array}{ccc}1 & 2 & 3 \\2 & 1 & 3 \\1 & -1 & -1\end{array}\right)$, use Cramer's Rule to find $\displaystyle x_2$ when $\displaystyle Ax=\left(\begin{array}{c}1 \\-2\\1\end{array}\right)$.

My current answer is $\displaystyle x_2=\frac{16}{3}$. Is this correct, or do I have to determine what $\displaystyle x$ is by inverting $\displaystyle A$?