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CUET · MATHS · PYQ PAPER 2025

Let \(M_{i j}\) and \(A_{i j}\) denote respectively minors and co-factors of the element in the ith row and jth column of the matrix \(A=\left[\begin{array}{ccc}1 & 2 & -1 \\ 3 & 2 & 3 \\ 4 & -1 & 0\end{array}\right]\). Then
(A) \(M_{32}=6\)
(B) \(M_{23}=9\)
(C) \(A_{32}=-6\)
\((D) A_{23}=-9\)
Choose the correct answer from the options given below :

  1. A (A) and (C) only
  2. B (A), (C) and (D) only
  3. C (B) and (D) only
  4. D (A) and (D) only
Verified Solution

Answer & Solution

Correct Answer

(A) (A) and (C) only

Step-by-step Solution

Detailed explanation

\(M_{32} = \begin{vmatrix} 1 & -1 \\ 3 & 3 \end{vmatrix} = (1)(3) - (-1)(3) = 6\) \(M_{23} = \begin{vmatrix} 1 & 2 \\ 4 & -1 \end{vmatrix} = (1)(-1) - (2)(4) = -9\) \(A_{32} = (-1)^{3+2} M_{32} = -1 \cdot (6) = -6\) \(A_{23} = (-1)^{2+3} M_{23} = -1 \cdot (-9) = 9\) (A) and (C)…
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