Question

If $A=\left[\begin{array}{c}-2\\ 4\\ 6\end{array}\right]$ and $B=[14-6]$ then find $AB$

Answer 1

$A=\left[\begin{array}{c}-2\\ 4\\ 6\end{array}\right]$

$B=\left[\begin{array}{ccc}1& 4& -6\end{array}\right]$

$AB=\left[\begin{array}{ccc}-2\times 1& -2\times 4& -2\times -6\\ 4\times 1& 4\times 4& 4\times -6\\ 6\times 1& 6\times 4& 6\times -6\end{array}\right]$

$\therefore AB=\left[\begin{array}{ccc}-2& -8& 12\\ 4& 16& -24\\ 6& 24& -36\end{array}\right]$