Ononot — For an invertible matrix A, the fundamental relationship A \

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Determinantshard

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For an invertible matrix $A$ , the fundamental relationship $A \cdot \text{adj}(A) = \det(A) \cdot I$ holds, where $\text{adj}(A)$ is the adjugate (classical adjoint) matrix. If $\det(A) = 4$ and the $(2,1)$ -entry of $\text{adj}(A)$ is 8, what is the $(2,1)$ -entry of $A^{-1}$ ?