If A = \(\begin{bmatrix}7 & 2\\ -4 & 1\end{bmatrix}\). find a formula for Aⁿ, where A = PDP^-1

P = \(\begin{bmatrix}1 & 1\\ -1 & -2\end{bmatrix}\) and D = \(\begin{bmatrix}5 & 0\\ 0 & 3\end{bmatrix}\)