Tom K. answered 07/22/20
Knowledgeable and Friendly Math and Statistics Tutor
√((x+√55)2 + y2) + √((x-√55)2 + y2) = 16 or
(8 cos t, 3 sin t) , 0 <= t < 2 π or
x2/64 + y2/9 = 1
Pick the one you prefer.
The first is from the definition of an ellipse as having the sum of the distance from the two foci equal to the distance between the major vertices.
The second is the parametric formula.
The third is the standard form.