Answer:
The center is (0,0) and the radius is 5
Explanation:
To find the center of a circle, you need to look at the equation
In this case this equation could be written as

The x value is x=0 for the center and the y values is y=0
The radius can be found by looking at the constant that is squared, so r=5
In the case of an equation like this

The center point would be (1,-1) and r=3