Answer:
(x+9)^2+(y+6)^2=36
Step-by-step explanation:
The equation of a circle is (x-h)^2+(y-k)^2=r^2 where (h,k) is the given center and r is the radius of the circle.
Given a center of (-9,-6) we have (x+9)^2+(y+6)^2=r^2 so far.
Since the diameter is 12, half of that is the radius which is 6, so the equation of the circle is (x+9)^2+(y+6)^2=36 (as 36 is 6^2)
