$A$ is a $2\times 2$ Matrix. $\vec{x} = 
\begin{pmatrix}-3\\
7 \\
\end{pmatrix}$ is an eigenvector and $\lambda\_{1} = 3$
is an eigenvalue.
I need to find $A\vec{x}$.

I am unsure how to do this and would like a little direction. This is a non-graded practice problem.