8. The circles \(C _ { 1 }\) and \(C _ { 2 }\) have respective equations $$\begin{aligned} & x ^ { 2 } + y ^ { 2 } - 6 x - 2 y = 15
& x ^ { 2 } + y ^ { 2 } - 18 x + 14 y = 95 \end{aligned}$$ a) By considering the coordinates of the centres and the lengths of the radii of \(C _ { 1 }\) and \(C _ { 2 }\), show that \(C _ { 1 }\) and \(C _ { 2 }\) touch internally at some point \(P\).
b) Determine the coordinates of \(P\).
c) Find the equation of the common tangent to the circles at P .