We are given the following function:

And we are asked to determine the average rate of change between points -8 and -4. To do this we will use the following formula for the average rate of change "R" of a function f(x) between points "a" and "b":

Replacing the points a = -8 and b = -4 in the formula we get:

Now we need to determine the value of the function at x = -4. To do this we will replace the value of -4 in the given function:

Solving the operations:

Now we replace the value of x = -8 in the function:

Solving the operations:

Now we replace the values of the function in the formula for the average rate of change:

Solving the operations:

Solving the fraction:

Therefore, the average rate of change is 110.
The same procedure can be used to solve for parts b and c.