Question

Given that $M=\left[\begin{array}{cc}3& -2\\ -4& 0\end{array}\right]andN=\left[\begin{array}{cc}-2& 2\\ 5& 0\end{array}\right]$, then $M+N$ is a

• A. null matrix
• B. unit matrix
• C. $\left[\begin{array}{cc}1& 0\\ 1& 0\end{array}\right]$
• D. $\left[\begin{array}{cc}0& 1\\ 1& 1\end{array}\right]$

Answer 1

The correct option is C $\left[\begin{array}{cc}1& 0\\ 1& 0\end{array}\right]$

Given: $M=\left[\begin{array}{cc}3& -2\\ -4& 0\end{array}\right]andN=\left[\begin{array}{cc}-2& 2\\ 5& 0\end{array}\right]$

Adding $M$ and $N$, we get

$M+N=\left[\begin{array}{cc}3& -2\\ -4& 0\end{array}\right]+\left[\begin{array}{cc}-2& 2\\ 5& 0\end{array}\right]=\left[\begin{array}{cc}1& 0\\ 1& 0\end{array}\right]$