The average rate of change is the slope between the given two points.
The formula of slope is :
[tex]\text{slope}=\frac{y_2-y_1}{x_2-x_1}[/tex]
So from x = 3 to x = 5
The points are :
[tex](3,-10)\rightarrow(x_1,y_1)[/tex]
and
[tex](5,-26)\rightarrow(x_2,y_2)[/tex]
Using the formula above :
The slope will be :
[tex]\text{slope}=\frac{-26-(-10)}{5-3}=\frac{-16}{2}=-8[/tex]
So the answer is D. -8
