Question

One endpoint of a line segment is (-7, 2). The midpoint of the line segment is (-1, -2). What are the co-ordinates of the other endpoint?

Answer 1

I don't want the answer just a formula

Answer 2

the other endpoint is just as far from the midpoint as the first end is. So, If you have points A,M,B, then

B = M + (M-A)
That is,
Bx = Mx + (Mx-Ax)
By = My + (My-Ay)

Or, as you can see, B = 2M-A

Answer 3

If (a,b) and (c,d) are any two points, then the midpoint is ((a+c)/2 , (b+d)/2) )

Answer 4

Thanks Steve:)