The distance between the points (x,21) and (4,7) is 10sqrt(3) Find the sum of all possible values of x.
Use distance formula
(x-4)^2 + (21-7)^2 = (10 sqrt3)^2
(x-4)^2 + 196 = 300
(x-4)^2 = 104
x^2 - 8x -88 = 0 Quadratic Formula shows x = 4 + 2 sqrt(26) and 4 - 2 sqrt (26) Add them together = 8