I am not sure of this answer:
An ellipse is a graph of points where the sum of the distances from two foci is a constant....
this looks like the equation for two distances from two foci
first foci would be 3 , -4 other is -5, 8
distance between these points is (3- -5)^2 + (-4 - 8)^2 = d^2
64 + 144 = d^2 d = sqrt 208