.For (a), find center and radius. For (b), explain why it has the same graph as (a).

(a) (x−5)2 +(y+3)2 =49 (b)x2 −10x+y2 +6y=15

a) the center is (5,-3) and the radius is the square root of 49 = 7.

(x-a)^2+(y-b)^2 = r^2 is the formula for the circle. This is why the center values are the opposite of what is in the formula above.