Question

If $A= $$\left[\begin{array}{cc}0& 1\\ 2& 4\end{array}\right]$$ B= $$\left[\begin{array}{cc}-1& 1\\ 2& 2\end{array}\right]$$ $,

and $C=\left[\begin{array}{cc}1& 0\\ 1& 0\end{array}\right],$ then $2A+3B-C=$

• A. $\left[\begin{array}{cc}-4& 5\\ 9& 14\end{array}\right]$
• B. $\left[\begin{array}{cc}4& 3\\ 9& 10\end{array}\right]$
• C. $\left[\begin{array}{cc}4& -5\\ 9& 14\end{array}\right]$
• D. $\left[\begin{array}{cc}-4& 5\\ 14& 9\end{array}\right]$

Answer 1

Answer: (A)

2A+3B-C=$\left|\begin{array}{cc}0& 2\\ 4& 8\end{array}\right|+\left|\begin{array}{cc}-3& 3\\ 6& 6\end{array}\right|-\left|\begin{array}{cc}1& 0\\ 1& 0\end{array}\right|=\left|\begin{array}{cc}-4& 5\\ 9& 14\end{array}\right|$