Final answer:
The diameter of the given circle is 34 units.
Step-by-step explanation:
To find the diameter of a circle, we need to know the radius. The equation of the circle can be rewritten in the standard form (x - h)^2 + (y - k)^2 = r^2, where (h, k) is the center of the circle and r is the radius. To find the radius, we need to complete the square for both x and y terms. Therefore, we have (x - 9)^2 + (y + 12)^2 = 289. The equation of a circle in standard form is (x - a)^2 + (y - b)^2 = r^2, where (a, b) is the center of the circle and r is the radius. Here, the center of the circle is (9, -12) and the radius is 17. The diameter of the circle is twice the radius, so the diameter is 34.