Answer
$$
-2
\begin{bmatrix}
7\\2\\9\\-3
\end{bmatrix}
-5
\begin{bmatrix}
-3\\1\\-6\\2
\end{bmatrix}
=
\begin{bmatrix}
1\\-9\\12\\-4
\end{bmatrix}
$$
Work Step by Step
From the definition of matrix-vector multiplication, we can expand the product. Since there are two columns, it is the equivalent of multiplying the first entry of the vector ($-2$) by the first column of the matrix, and doing the same for the second entry and column. We sum them together (this is the definition of matrix-vector multiplication), and the product equals the right hand side of the equation provided.
