Step-by-step Answer:
The coordinates of the mid-point of a segment whose end-points are known is the average of the coordinates of the end-points.
Here, the end-points are: (-11,0), (9,-1)
So the x-coordinate of the mid-point is (-11+9)/2 = (-2/2) = -1, and
the y-coordinate of the mid-point is (0-1)/2 = -0.5
So the mid-point is (-1,-0.5)
Check the numbers by plotting the point on the graph!