Answer: The other endpoint of the segment is (-1, -11).
Step-by-step explanation: Given that the midpoint of a line segment is (6, -6) and one endpoint is (13, -1).
We are to find the co-ordinates of the other endpoint.
Let (a, b) be the co-ordinates of the other end-point.
Then, according to the given information, we have

Equating the x and y co-ordinates on both sides of the above, we get

and

Thus, the other endpoint of the segment is (-1, -11).