Question

Find multiplication of following matrix:
$\left[\begin{array}{cc}6& 4\\ 3& -1\end{array}\right]\left[\begin{array}{c}-1\\ 3\end{array}\right]$

Answer 1

$\left[\begin{array}{cc}6& 4\\ 3& -1\end{array}\right]\left[\begin{array}{c}-1\\ 3\end{array}\right]$

$=\left[\begin{array}{cc}6\times -1+4\times 3& (3-1)+(-1\times 3)\end{array}\right]=\left[\begin{array}{cc}-6+12& -3-3\end{array}\right]$

$=\left[\begin{array}{cc}6& -6\end{array}\right]$