5. The circle \(C\) has equation
$$x ^ { 2 } + y ^ { 2 } - 10 x + 6 y + 30 = 0$$
Find
- the coordinates of the centre of \(C\),
- the radius of \(C\),
- the \(y\) coordinates of the points where the circle \(C\) crosses the line with equation \(x = 4\), giving your answers as simplified surds.