Question

If $A=\left[\begin{array}{cc}2& -1\\ 3& 4\end{array}\right]B=\left[\begin{array}{cc}5& -2\\ 7& 4\end{array}\right]$ and $C=\left[\begin{array}{cc}2& 5\\ -3& -8\end{array}\right],$ find the value of $A+B+C$

Answer 1

$A+B+C=\left[\begin{array}{cc}2& -1\\ 3& 4\end{array}\right]+\left[\begin{array}{cc}5& -2\\ 7& 4\end{array}\right]+\left[\begin{array}{cc}2& 5\\ -3& -8\end{array}\right]$

$=\left[\begin{array}{cc}2+5+2& -1-2+5\\ 3+7-3& 4+4-8\end{array}\right]$

$=\left[\begin{array}{cc}9& 2\\ 7& 0\end{array}\right]$