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Let A = [ array ll 1 & 2 3 & 4 array ]= [a_ i j ] , where i, j,=1,2 . If its inverse matrix is [b_ i j ] , what is b₂₂ ?

Options

  1. A-2
  2. B1
  3. C3 2
  4. D- 1 2

Correct answer

D. - 1 2

Step-by-step solution

aligned & | A |=4-6=-2 & ~A ⁻¹= [ b _ ij ]= 1 -2 [ array cc 4 & -2 -3 & 1 array ]= [ array cc -2 & 1 3 2 & - 1 2 array ] aligned b ₂₂=- 1 2

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