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

Question

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

Answer 1

midpoint formula:( x₁ + x₂ ) / 2 = x_midpoint

                          (y₁ + y₂) / 2 = y_midpoint

x₁ = -3, y₁ = -1

x_midpoint = -1

y _midpoint = 1

(-3 + x₂ ) /2 = -1 ---> -3 + x₂ = -2 -->x₂ = 1

(-1 + y₂) /2= 1 --> -1 + y₂ = 2 --> y₂ = 3

therefore (x_2, y₂) = (1, 3)