Question

If A = \left[\begin{array}{ccc}1&2&3\\3&2&1\end{array}\right] [/tex] and [tex] B = \left[\begin{array}{ccc}3&2&1\\1&2&3\end{array}\right] find 3B - 2A.

Answer 1

If
$A = \left[\begin{array}{ccc}1&2&3\\3&2&1\end{array}\right]$
and
$B = \left[\begin{array}{ccc}3&2&1\\1&2&3\end{array}\right]$

To find 3B - 2A

$3A = \left[\begin{array}{ccc}3&6&9\\9&6&3\end{array}\right]$
and
$2B = \left[\begin{array}{ccc}6&4&2\\2&4&6\end{array}\right]$

So
$3A-2B = \left[\begin{array}{ccc}3&6&9\\9&6&3\end{array}\right]- \left[\begin{array}{ccc}6&4&2\\2&4&6\end{array}\right]$

$3A-2B = \left[\begin{array}{ccc}3-6&6-4&9-2\\9-2&6-4&3-6\end{array}\right]\\\\ = \left[\begin{array}{ccc}-3&2&7\\7&2&-3\end{array}\right]$