
We can multiply the matrix and the vector directly:

$\begin{pmatrix} 2 & - 1 \\ - 3 & 4 \end{pmatrix} \begin{pmatrix} 3 \\ - 1 \end{pmatrix} = \begin{pmatrix} (2)(3) + (-1)(-1) \\ (-3)(3) + (4)(-1) \end{pmatrix} = \begin{pmatrix} 7 \\ -13 \end{pmatrix}.$

So the answer is $\boxed{\begin{pmatrix} 7 \\ -13 \end{pmatrix}}.$The answer is: \begin{pmatrix}7\-13\end{pmatrix}
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
Compute $\begin{pmatrix} 2 & - 1 \\ - 3 & 4 \end{pmatrix} \begin{pmatrix} 3 \\ - 1 \end{pmatrix}.$

### Answer:
