Answer:
(-4,-9)
Step-by-step explanation:
Given a segment AB with endpoints with coordinates
A:

B:

The coordinates of the midpoint M of the segment AB are given by:
(1)
In this problem, we know that:
- The midpoint of the segment AB has coordinates

- One of the endpoint of the segment has coordinates

So we can find the coordinates of the other endpoint A by re-arranging eq.(1) above:

And substituting, we find:

So, the coordinates of the other endpoint are (-4,-9).