Answer:
-3
Step-by-step explanation:
The average rate of change is the slope of the line that connects the points of interest. At x=-6, the point is (-6, 8). At x=-5, the point is (-5, 5).
I find it easy to refer to the graph to see that the point at x=-5 is 3 units down and 1 unit to the right of the point at x=-6. So the slope of the connecting line is -3/1 = -3.
If you want to find the same result analytically, you can compute ...
... ∆y/∆x = (y2 -y1)/(x2 -x1)
... = (5 -8)/(-5 -(-6))
... = -3/1 = -3
