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CUET · MATHS · PYQ PAPER 2025

If \(A=\left[\begin{array}{ccc}2 & 1 & -1 \\ 0 & 1 & 2 \\ 2 & -1 & \lambda\end{array}\right]\) is a singular matrix, then the value of \(\lambda\) is:

  1. A 0
  2. B 3
  3. C 5
  4. D -5
Verified Solution

Answer & Solution

Correct Answer

(D) -5

Step-by-step Solution

Detailed explanation

\(|A| = 2(1 \cdot \lambda - 2 \cdot (-1)) - 1(0 \cdot \lambda - 2 \cdot 2) + (-1)(0 \cdot (-1) - 1 \cdot 2) = 0\) \(2(\lambda + 2) - 1(-4) - 1(-2) = 0\) \(2\lambda + 4 + 4 + 2 = 0\) \(2\lambda + 10 = 0\) \(2\lambda = -10\) \(\lambda = -5\)
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