Expressing the product Ax as a linear combination of the column vectors of
$A$= $\begin{bmatrix} 4 & 0 & -1\\ 3 & 6 & 2\\ 0 & -1 & 4 \end{bmatrix}$
$\vec{x}$=$\begin{bmatrix} -2\\ 3\\ 5 \end{bmatrix}$
I get it now. They just want me to multiply the two vectors together.
I end up with $\begin{bmatrix} -13\\\ 22\\\ 17 \end{bmatrix}$