[QUE/QM-06019]

Using spectral theorem, or otherwise, show that \begin{equation} \exp(i\hat{P}a) (\hat{x})^n \exp(-i\hat{P}a ) = (\hat{x}+a)^n, \end{equation} where \(n\) is an integer and  \(\hat{P}\) and \(\hat{x}\) are the momentum  and  position operators.