MCQ
If $\text{A}=\begin{bmatrix}2&5&9\\6&1&3\\4&8&2\end{bmatrix},$ find $|\text{A}|$
  • $352$
  • B
    $356$
  • C
    $325$
  • D
    $532$

Answer

Correct option: A.
$352$
$\Rightarrow|\text{A}|=\begin{bmatrix}2&5&9\\6&1&3\\4&8&2\end{bmatrix}$ Evaluating along the first row, we get
$\triangle=2\begin{bmatrix}1&3\\8&2\end{bmatrix}-5\begin{bmatrix}6&3\\4&2\end{bmatrix}+9\begin{bmatrix}6&1\\4&8\end{bmatrix}$
$\triangle=2(2-24)-5(12-12)+9(48-4)$
$\triangle=2(-22)-0+9(44) $
$\triangle=-44+9(44)=44(-1+9)=352 $

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