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If A , B and C are square matrices of order 3 and A = 2 , B = 3 and C = 4 , then the value of 3 a d j A B C - 1 is equal to (where, a d j A represents the adjoint matrix of A )

Options

  1. A27
  2. B27 4
  3. C81 2
  4. D81

Correct answer

D. 81

Step-by-step solution

3 a d j A B C - 1 = 3 3 a d j A ⋅ B C = 3 3 × A 2 ⋅ B C = 3 3 × 2 2 × 3 4 = 8 1

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