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AP EAMCET202315 May 2023Evening ShiftMathematicsMatricesActual

If the cofactors of the elements 3,7 and 6 of the matrix [ array ccc 1 & 2 & 3 4 & -1 & 7 2 & 4 & 6 array ] are a, b and c respectively, then [ array lll a & b & c array ] [ array l 1 4 2 array ]+ [ array lll a & b & c array ] [ array l 3 7 6 array ]=

Options

  1. A-1
  2. B1
  3. C0
  4. D3

Correct answer

C. 0

Step-by-step solution

In the given matrix aligned & C₁₃=(-1)¹⁺³(16+2) a=18 & C₂₃=(-1)²⁺³(4-4) b=0 & C₃₃=(-1)³⁺³(-1-8) c=-9 aligned Now, aligned & [ array lll 18 & 0 & -9 array ] [ array l 1 4 2 array ]= [ array lll 18 & 0 & 9 array ] [ array l 3 7 6 array ] & = [ array lll 18 & 0 & -9 array ] [ array c 4 11 8 array ]=[72-72]=[0]=0 aligned

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