Question

The foci of the ellipse 25(x + 1)² + 9(y + 2)² = 225, are at

(a)  (–1,2) & (–1,–6)

(b) (–2,1) and (–2,6)

(c)  (–1,–2) & (–2,–1)

(c)  (–1,–2) and (–1,–6)

Answer 1

Correct option (a) (–1,2) & (–1,–6)

Explanation:

Here equation of ellipse is

25(x + 1)² + 9(y + 2)² = 225

0r (x + 1)²/9 + (y + 2)²/25 = 1

Centre of the ellipse is (–1,–2)

a² = 9

b²  = 25

a = 3 b = 5

e =  ± 4/5

be =  ± 4

Foci is (–1,–2 ± 4) (–1,–6) & (–1,2)