Distance Formula

Question

Find all of the points of the form (x, −1) which are 4 units from the point (3, 2).

Answer 1

(x-3)^2 + (y-2)^2 = 4^2

(x-3)^2 +(-1-2)^2 = 16

x^2 -6x + 9 = 16-9= 7

(x-3)^2 = 7

x -3 = +/-sqr7

x = 3+/-sqr7

the two points are (3+sqr7, -1) and (3-sqr7, -1)