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Question: Answered & Verified by Expert
If $\mathrm{p}=\left[\begin{array}{lll}1 & \alpha & 3 \\ 1 & 3 & 3 \\ 2 & 4 & 4\end{array}\right]$ is the adjoint of the $3 \times 3$ matrix $\mathrm{A}$ and $\operatorname{det} \mathrm{A}=4$, then $\alpha$ is equal to
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Options:
  • A 4
  • B 11
  • C 5
  • D 0
Solution:
2225 Upvotes Verified Answer
The correct answer is: 11
$|\mathrm{p}|=2 \alpha-6=(\operatorname{det} \mathrm{A})^2=16$
$\Rightarrow \alpha=11$

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