Answer:
Step-by-step explanation:

The radius is from center to point on a circle.
So your task is count distance between two points: S(10,6) and A(-3,3).
Distance between two points A(x1, y1) and B(x2, y2) count from this formula:
The remainder is or answer is 6
Parallel = same slope
y = -2/3x + b
Plug in point
15 = -2/3(-3) + b
15 = 2 + b, b = 13
Solution: y = -2/3x + 13