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CUET · MATHS · PYQ PAPER 2025

If \(A =\left(\begin{array}{cc}2 & 3 \\ 5 & -2\end{array}\right)\), be such that \(A ^{-1}=K A\), then the value of \(K\) is :

  1. A \(19\)
  2. B \(\frac{1}{19}\)
  3. C \(0\)
  4. D \(-19\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(\frac{1}{19}\)

Step-by-step Solution

Detailed explanation

\( \det(A) = (2)(-2) - (3)(5) = -4 - 15 = -19 \) \( A^{-1} = \frac{1}{\det(A)} \operatorname{adj}(A) = \frac{1}{-19} \begin{pmatrix} -2 & -3 \\ -5 & 2 \end{pmatrix} = \frac{1}{19} \begin{pmatrix} 2 & 3 \\ 5 & -2 \end{pmatrix} \)…