If $A = \begin{bmatrix}1&2\\0&3\end{bmatrix}$, then $|A\, adj\,A|$ is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 9 **
Given:
$A=\begin{bmatrix}1 & 2 \\ 0 & 3\end{bmatrix}$
For any square matrix:
$|A\,\text{adj}\,A| = |A|^{n}$ for an $n\times n$ matrix.
Here $n=2$.
Compute $|A|$:
$|A| = 1\cdot 3 - 2\cdot 0 = 3$
Thus:
$|A\,\text{adj}\,A| = |A|^{2} = 3^{2} = 9$