If A is a 3 × 3 matrix such that 5 a d j A = 5 , then A is equal to

5 A d j A = 5 125 | a d j A | = 5 Since [ A ] is 3 × 3 a d j A = 1 25 A 2 = 1 25 A = ± 1 5 .

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MathematicsMatricesAdjointMedium2 minPYQ_2015

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If $A$ is a $3 \times 3$ matrix such that $|5 a d j A| = 5$ , then $|A|$ is equal to

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Answer:

Solution:

$|5 A d j A| = 5$

$125 | a d j A | = 5$

Since $[A]$ is $3 \times 3$

$|a d j A| = \frac{1}{25}$

${|A|}^{2} = \frac{1}{25}$

$|A| = \pm \frac{1}{5} .$

Stream:JEESubject:MathematicsTopic:MatricesSubtopic:Adjoint

⏱ 2mℹ️ Source: PYQ_2015

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