Question

For matrices $A=\left[\begin{array}{cc}2& 1\\ 3& 2\end{array}\right]$ and $B=\left[\begin{array}{cc}2& 3\\ 1& 2\end{array}\right]$, write $A+B$ and $A-B$.

Answer 1

If $A,B$ are two matrices, then $A+B,A-B$ can be obtained by adding or subtracting corresponding elements in the matrices respectively.

$A=\left[\begin{array}{cc}2& 1\\ 3& 2\end{array}\right]$ , $B=\left[\begin{array}{cc}2& 3\\ 1& 2\end{array}\right]$

$\Rightarrow A+B=\left[\begin{array}{cc}4& 4\\ 4& 4\end{array}\right]$

$\Rightarrow A-B=\left[\begin{array}{cc}0& -2\\ 2& 0\end{array}\right]$