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

Options

  1. A± 1 25
  2. B± 5
  3. C± 1 5
  4. D± 1

Correct answer

C. ± 1 5

Step-by-step solution

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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