(-3,-1) and (-1,1) find the other endpoint?

Question

An endpoint and the midpoint of a ling segment are respectively (-3,-1) and (-1,1). Find the other endpoint.

Answer 1

(x1 + x2)/2, (y1 + y2)/2 is the formula for midpoint.  Since you have the midpoint and one end point set it up like:

(-3 + x2)/2 = -1

(-3 + x2) = -2 (multiply both sides by 2

x2 = 1 (add 3 to both sides.)

 

(-1 + y2) / 2 = 1

(-1 + y2) = 2 (multiply both sides by 2

y2 = 3 (add 1 to both sides).

Your endpoint therefor is (1, 3)