Hello!
The equation of a circle is
(x - h)^2 + (y - k)^2 = r^2
Put in the values we know
(x - h)^2 + (y - 7)^2 = 10^2
It went through point (3, -1)
(3 - h)^2 + (-1 - 7)^2 = 100
(3 - h)^2 + (-8)^2 = 100
(3 - h)^2 + 64 = 100
Subtract 64 from both sides
(3 - h)^2 = 36
Take the square root of both sides
3 - h = +6 or -6
Subtract 3 from both sides
-h = 3 or -9
Since h is negative we can multiply both sides by -1 to make it positive
3 = -3 or 9
The answer is B) 9, -3
Hope this helps!
