find the points

Question

Find all points having an​ x-coordinate of 8 whose distance from the point (3​,−9​) s 13.

Answer 1

(x - 3)² + (y + 9)² = 169 define all points 13 units from (3, -9)

You want the points in which x = 8

(8 - 3)² + (y + 9)² = 169

25 + (y + 9)² = 169

(y + 9)² = 144

y + 9 = ±12

y = 3 or y = -21

The points are (8, 3) and (8, -21)