Rearranging the equation,
x2 + y2 + 26x + 34y + 97 = 0
x2 + 26x + y2 + 34y + 97 = 0
(x2 + 2×13×x + 132) - 169 + (y2 + 2×17×y + 172) - 289 + 97 = 0
(x+13)2 + (y+17)2 - 361 = 0
[x−(−13)]2 + [y−(−17)]2 = 192
So the circle's centre is at (-13, -17) and its radius is 19 units.