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KCET2025MathematicsDeterminants

If A= [ array ll k & 2 2 & k array ] and | A ^3 |=125 , then the value of k is

Options

  1. A2
  2. B3
  3. C-5
  4. D-4

Correct answer

B. 3

Step-by-step solution

aligned & A= [ array ll k & 2 2 & k array ] & | A |= k ^2-4 & | ~A |^3=| A | | A | | A |=125 , given & ( k ^2-4 )^3=125 & k ^2-4=5 k ^2=9 & k = 3 aligned

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