From the relation of following equation
${(s\textbf{I}-\textbf{A})^{-1}} = \frac{1}{\Delta(s)} \text{adj}((s\textbf{I}-\textbf{A}))$,
the textbook says $\psi(s)=\Delta(s)/m(s)$.
$\Delta(s)$ means $\det(s\textbf{I}-\textbf{A})$,
$\psi(s)$ means the minimal polynomial of $\textbf{A}$,
and $m(s)$ means the monic greatest common divisor of all elements of $\text{adj}((s\textbf{I}-\textbf{A}))$.
But I can't derive the relation above. How to prove $\psi(s)=\Delta(s)/m(s)$?