You must memorize this:
(x-h)2 + (y-k)2 = r2
And that the center is (h,k) and the radius is r
Your equation is
x2 + (y-3)2 = 25
You want to rewrite it so that looks like this:
(x-h)2 + (y-k)2 = r2
To make x look like (x-h) write it as (x-0)
(y-3) already looks like (y-k)
To make 25 look like r2, write it as 52
Then you have this equation:
(x-0)2 + (y-3)2 = 52
And when you compare it to this equation which you memorize,
(x-h)2 + (y-k)2 = r2
And you see that -0=-h or h=0, and -3=-k or k=3 and r2=52
and so r=5.
So the center is (h,k) = (0,3) and radius = r = 5. The graph is
Edwin
