Question

Compute the product $\left[\begin{array}{ccc}-1& 3& 0\\ 2& 1& 4\end{array}\right]\times \left[\begin{array}{cc}1& 3\\ 0& 2\\ -2& -1\end{array}\right]$

• A. $\left[\begin{array}{cc}1& 3\\ 6& -4\end{array}\right]$
• B. $\left[\begin{array}{cc}-1& -3\\ 6& 4\end{array}\right]$
• C. $\left[\begin{array}{cc}-1& 3\\ -6& 4\end{array}\right]$
• D. $\left[\begin{array}{cc}-1& 3\\ -6& -4\end{array}\right]$

Answer 1

Answer: (C)

$\left[\begin{array}{ccc}-1& 3& 0\\ 2& 1& 4\end{array}\right]\left[\begin{array}{cc}1& 3\\ 0& 2\\ -2& -1\end{array}\right]$
$=\left[\begin{array}{cc}-1+0+0& -3+6+0\\ 2+0-8& 6+2-4\end{array}\right]=\left[\begin{array}{cc}-1& 3\\ -6& 4\end{array}\right]$