Determine the end point of the line segment AB if B(-2,12) and the midpoint is ( 2,5)

Given the line segment AB such that B(-2, 12) and the
midpoint m(2,5).

We need to find the coordinates of the
point A.

We will use the midpoint formula to find
A.

We know that:

xm = (
xA+xB)/2

==> 2 =
(-2+xB)/2

Multiply by
2.

==> 4 = -2 +
xB

==> xB = 4+2 =
6

==> xB = 6

Also we
know that:

ym =
(yA+yB)/2

==> 5 = (12 +
yB)/2

==> (12+yB =
10

==> yB =
-2

Then, the point B is : B(6, -2)