**tangent of equation x + 3y = 1 at A (1,0)**

the equation of radius CA is

**y = 3x + 3 .**

(also given info about a chord joining A and B (5,4) - eqn. of AB's perpendicular bisector is x + 3y = 1 but i dont think this helps)

Determine the coordinates of point C.

Is this a distance formula question? confused.