A = (-2,1) B = (4,1)
The side length of AB = 6
And C will have an x coordinate value of (4 - 2) / 2 = 2/2 = 1
So...C = (1, y)
So....we can find the possible y values of C by setting the distance between A and C = 6...so we have
sqrt [ (-2 - 1)^2 + ( y - 1)^2 ] = 6 square both sides
(-2 - 1)^2 + (y - 1)^2 = 36 simplify
(-3)^2 + (y - 1)^2 = 36
9 + (y - 1)^2 = 36 subtract 9 from both sides
(y - 1)^2 = 27 take both roots
y - 1 = ±√27
y = ±3√3 + 1 = -4.2 and 6.2
So...the possible coordinates for C are
(1, -4.2) and (1, 6.2)