Matrices - Addition and Subtraction of Matrices

It is given that matrices \(\mathbf{P} = \begin{pmatrix} 3y & 1 \\ 2 & 3 \end{pmatrix}\), \(\mathbf{Q} = \begin{pmatrix} y & 4 \\ 8 & 2 \end{pmatrix}\) and \(\mathbf{R} = \begin{pmatrix} 5 & 1 \\ 2 & 8 \end{pmatrix}\).

If \(3\mathbf{P} - \frac{1}{2}\mathbf{Q} = \mathbf{R}\), find the value of \(y\).