the true question should be like this:
What is the center and radius of the following circle: x^2 + (y _ 6)^2 = 50,
circle quation formula is (x-a)^2 + (y-b)^2 = R², so by identifying each term, we find (x-a)^2=x^2 = (x-0)^2, (y-b)^2= (y _ 6)^2, R² = 50, implies R =5sqrt(2),
it is easy to identify that the center is (a,b)= (0, 6)
the radius is R =5sqrt(2),