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CUET · MATHS · PYQ PAPER 2025

Let A = \(\left[\begin{array}{ccc}152 & 105 & 3 \\ 149 & 25 & 35 \\ 2 & 1 & 0\end{array}\right]\) . If \(A_{i j}\) denotes the co-factor of an element \(a_{i j}\) of the matrix A, then the value of \(a_{11} A_{21}+a_{12} A_{22}+a_{13} A_{23}\) is equal to

  1. A -1
  2. B 0
  3. C 1
  4. D 1529
Verified Solution

Answer & Solution

Correct Answer

(B) 0

Step-by-step Solution

Detailed explanation

\(A_{21} = - \det\left[\begin{array}{cc}105 & 3 \\ 1 & 0\end{array}\right] = -(105 \cdot 0 - 3 \cdot 1) = 3\) \(A_{22} = + \det\left[\begin{array}{cc}152 & 3 \\ 2 & 0\end{array}\right] = (152 \cdot 0 - 3 \cdot 2) = -6\)…