Answer:
a) The center coordinates O is (0,0)
b) The radius C = 15
Step-by-step explanation:
The given equation of the circle is : 
Now, general form of the equation of the circle is:

where (h,k) are the center co -ordinates and r is the radius of the circle.
Comparing the general equation with the given equation, we get

So, here the center coordinates (h,k) = (0,0)
And the radius of the given circle is r = 15