Given the vectors \(\mathbf{U}=\begin{pmatrix}7 \\ 6\end{pmatrix}\) and \(\mathbf{V}=\begin{pmatrix}2 \\ x\end{pmatrix}\), find the value or values of \(x\) for which

- \(\mathbf{U}\) is parallel to \(\mathbf{V}\),
- \(\mathbf{U}\) is perpendicular to \(\mathbf{V}\),
- \(\mathbf{U}\) and \(\mathbf{V}\) have the same magnitude.