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CUET · MATHS · PYQ PAPER 2023

The sum of the minor and the cofactor of the element 6 in the determinant \(\Delta=\left|\begin{array}{lll}2 & 3 & 1 \\ 4 & 5 & 6 \\ 7 & 8 & 9\end{array}\right|\) is:

  1. A \(-5\)
  2. B \(-10\)
  3. C 10
  4. D \(0\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(0\)

Step-by-step Solution

Detailed explanation

Element 6 is at position \( (2,3) \). Sum of indices \( = 2+3=5 \) (odd). \( C_{23} = -M_{23} \). Sum \( = M_{23} + C_{23} = M_{23} - M_{23} = 0 \).