Radii of the circles are :
R1 : √5
R2 : √5/2
R3 : 3√5
Common tangent of S1 and S2 is
T1 : 6x - 3y + 9 = 0 => y = 2x + 3
Similarly,
T2 : 2x + 2y + 9 = 0 => y = -x - 9/2
T3 : x + 2y + 9 = 0 => y = -x/2 - 9/2
Point of contact is (-a2m/c, a2/c).
P1 : (-2 x 5/3, 5/3) or ( -10/3, 5/3 )
P2 : (5/18, -5/18)
P3 : (5, 10)
Some silly mistake I've made...P2 and P3 don't seem reflections at at all.