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If A = 1 1 2 1 3 4 1 - 1 3 , B = a d j A and C = 3 A , then a d j B C is equal to

Options

  1. A8
  2. B16
  3. C72
  4. D2

Correct answer

A. 8

Step-by-step solution

A = 1 1 2 1 3 4 1 - 1 3 = 9 + 4 - 1 3 - 4 + 2 - 1 - 3 = 13 + 1 - 8 = 6 a d j B = a d j a d j A = A n - 1 2 = A 4 = 36 2 C = 3 A = 3 3 × 6 a d j B C = 36 × 36 3 3 × 6 = 8

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