10.
\includegraphics[max width=\textwidth, alt={}, center]{af6fdbed-fcab-4db8-9cdf-fd049ce720fd-3_668_787_918_431}
The diagram shows the circle \(C\) and the straight line \(l\).
The centre of \(C\) lies on the \(x\)-axis and \(l\) intersects \(C\) at the points \(A ( 2,4 )\) and \(B ( 8 , - 8 )\).
- Find the gradient of 1 .
- Find the coordinates of the mid-point of \(A B\).
- Find the coordinates of the centre of \(C\).
- Show that \(C\) has the equation
$$x ^ { 2 } + y ^ { 2 } - 18 x + 16 = 0$$