How to do it and answer

Answer:
(0,0)
Step-by-step explanation:
Let's put this in standard form in our minds.
Standard form of a circle is (x-h)^2 + (y-k)^2 = r^2.
(h,k) is the center, and r is the radius.
x^2 + y^2 = 121
(x-0)^2 + (y-0)^2 = 121
We can just think about this like they have a secret 0 as the h and k! The center is just (0,0). Good luck in your math class:)