Question

Please, find the coordinate of the other endpoint of a segment with the given endpoint and midpoint M:

R(2,6)
M(-1,1)

Answer 1

Let (x,y) be the coordinates of other endpoint.
The expressions for the coordinate of midpoint are
(x+2)/2=-1 and (y+6)/2=1;
thus
x=-4; y=-4
The answer: L(-4,-4)