9. The circle \(C\) has centre \(( - 3,2 )\) and passes through the point \(( 2,1 )\).
- Find an equation for \(C\).
- Show that the point with coordinates \(( - 4,7 )\) lies on \(C\).
- Find an equation for the tangent to \(C\) at the point ( - 4 , 7). Give your answer in the form \(a x + b y + c = 0\), where \(a , b\) and \(c\) are integers.