# Addition and Subtraction on Matrices (Sample Questions)

Example 1:
Find the addition of the following matrices.

Example 2:
Find the subtraction of the following matrices.

Example 3:
Given that , find the values of p and q.

$\begin{array}{l}\left(\begin{array}{l}p\\ q\end{array}\right)+\left(\begin{array}{l}5p\\ 9\end{array}\right)=\left(\begin{array}{l}-12\\ 3q+1\end{array}\right)\\ \left(\begin{array}{l}p+5p\\ q+9\end{array}\right)=\left(\begin{array}{l}-12\\ 3q+1\end{array}\right)\end{array}$

p + 5p = -12
6p = -12
p = -2
q + 9 = 3q + 1
q – 3q = 1 – 9
-2q = -8
q = 4

Example 4:
Find the values of m and n in the following matrix equation.
$\left(\begin{array}{cc}7& 6\\ n& 1\end{array}\right)-\left(\begin{array}{cc}-1& m\\ -4& -2\end{array}\right)=\left(\begin{array}{cc}5& 12\\ 6& 11\end{array}\right)$

$\left(\begin{array}{cc}7& 6\\ n& 1\end{array}\right)-\left(\begin{array}{cc}-1& m\\ -4& -2\end{array}\right)=\left(\begin{array}{cc}5& 12\\ 6& 11\end{array}\right)$