In Problem a-c, find the equation of the set of points P satisfying the given conditions. a.

Question:

In Problem a-c, find the equation of the set of points P satisfying the given conditions.
a. The sum of the distances of P from (0, ±9) is 26.
b. The sum of the distances of P from (±4, 0) is 14.
c. The sum of the distances of P from (±7, 0) is 12.