Question

Find the Coordinates of the other endpoint of a segment wiht one endpoint X(4,-6) and the midpoint M(1,5)

Answer 1

X(4,-6)
M(1,5)
Since M is the mid point, then Y(x,y) should be a point such that
(4+x)/2=1, and (-6+y)/2=5.

For example:
(4+x)/2 = 1
4+x=2
x=2-4=-2

I'll leave it to you to solve for y.