Question

If matrix \( A = \begin{bmatrix} 3 & -2 & 4 \\ 1 & 2 & -1 \\ 0 & 1 & 1 \end{bmatrix} \) and \( A^{-1} = \frac{1}{k} adj(A) \), then \( k \) is

• A. 7
• B. -7
• C. 15
• D. -11

Hint:

Remember the formula \( A^{-1} = \frac{1}{det(A)} adj(A) \).