MCQ
If $A=\left[\begin{array}{lll}2 & -3 & 4\end{array}\right], B=\left[\begin{array}{l}3 \\ 2 \\ 2\end{array}\right], X=\left[\begin{array}{lll}1 & 2 & 3\end{array}\right]$ and $Y=\left[\begin{array}{l}2 \\ 3 \\ 4\end{array}\right]$, then $A B+X Y$ equals
  • $[28]$
  • B
    $[24]$
  • C
    $28$
  • D
    $24$

Answer

Correct option: A.
$[28]$
Consider, $A B=\left[\begin{array}{lll}2 & -3 & 4\end{array}\right]\left[\begin{array}{l}3 \\ 2 \\ 2\end{array}\right]$
$=[6-6+8]=[8]$
and $X Y=\left[\begin{array}{lll}1 & 2 & 3\end{array}\right]\left[\begin{array}{l}2 \\ 3 \\ 4\end{array}\right]$
$=[2+6+12]=[20]$
$A B+X Y=[8]+[20]=[28]$

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