Question

Let $A=\left[\begin{array}{c}-1\\ 2\\ 3\end{array}\right]$ and $B=\left[\begin{array}{ccc}-2& -1& -4\end{array}\right]$

Let $K=1$ in matrix $A$ then $(AB{)}^{\prime }$ equals to

• A. $\left[\begin{array}{ccc}2& -4& -6\\ 1& -2& -3\\ 4& -8& -12\end{array}\right]$
• B. $\left[\begin{array}{ccc}2& 1& 4\\ -4& -2& -8\\ -6& -3& 12\end{array}\right]$
• C. $\left[\begin{array}{ccc}-2& 4& 6\\ -1& 2& -3\\ -4& 8& 12\end{array}\right]$
• D. $\left[\begin{array}{ccc}-2& -1& -4\\ 4& 2& 8\\ 6& 3& 12\end{array}\right]$

Answer 1

The correct option is A $\left[\begin{array}{ccc}2& -4& -6\\ 1& -2& -3\\ 4& -8& -12\end{array}\right]$

Here, $A=\left[\begin{array}{c}-1\\ 2\\ 3\end{array}\right],B=\left[\begin{array}{ccc}-2& -1& -4\end{array}\right]$
$AB=\left[\begin{array}{ccc}2& 1& 4\\ -4& -2& -8\\ -6& -3& -12\end{array}\right]$
$(AB{)}^{\prime }=\left[\begin{array}{ccc}2& -4& -6\\ 1& -2& -3\\ 4& -8& -12\end{array}\right]$