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Question: Answered & Verified by Expert
Let $A$ be a $3 \times 3$ matrix and $B$ be its adjoint matrix. If $|B|=64,$ then $|A|$ is equal to
MathematicsMatricesWBJEEWBJEE 2016
Options:
  • A ±2
  • B $\pm 4$
  • C $\pm 8$
  • D ±12
Solution:
2530 Upvotes Verified Answer
The correct answer is: $\pm 8$
We have,
$|B|=64$
$\Rightarrow |\operatorname{adj} A \mid=64$
$\Rightarrow|A|^{2}=64$
$|A|=\pm 8$

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