Question

An equilateral triangle has two vertices at the points (1,1) and (-1,1). Find the coordinates of third vertex

Answer 1

Distance between these two points = 2
Let x,y be the third point.
Then distnace between x,y and 1,1 will be equal to distance between x,y and 1,-1 which will be equal to 2.
Solving this will lead to your solution.