Please help me finish a circles question (C2)

The circle c1 has centre A and equation x² + y² - 6x + 2y - 15 =0
for part a) i worked out that the coordinates of A are (3, -1) and r = 5..

for part b)
The point P has coordinates (7,2) and lies on c1. Find the equation of the tangent to c1 at P.
I did this. The answer is y - 2 = -4/3 (x-7)

HOW DO I DO PART C) though?

c) The circle c2 has centre B (11,14) and radius 8. A point Q lies on c1 and a point R lies on c2. Find the shortest possible length of the line QR.

Thanks

The shortest distance between two circles has to be a segment of the line that connects the centres of each. You know that the two circles have centres (3, -1) and (11,14). You can work out the length of this line easily using the equation or Pythagoras' Theorem. As the x increase is 8 and the y increase is 15, it's 17. You also know that the radius of one circle is 5 and the other is 8. So deduct (8+5)=13 from the length you found. This gives 4 as your answer.