Answer:
-1.5
Step-by-step explanation:
The middle of a line segment is its midpoint. To find the midpoint of a line segment, you just calculate the averages of the coordinates.
If a line segment on a number line has its endpoints at -9 and 6, then the coordinate of midpoint is
[tex]\dfrac{-9+6}{2}=\dfrac{-3}{2}=-1.5[/tex]