Answer:
-17
Step-by-step explanation:
The average rate of change is synonymous to the slope of a function.
We want to find the average rate of change for the function:
For the interval [3, 4]
So, we simply have to calculate the values of the function at the endpoints and then find the slope between them.
Our endpoint values are x=3 and x=4. So:

And:

So, we have the two points (3, -35) and (4, -52).
Now, we can use the slope formula:

Calculate the slope:

Hence, the slope or the average rate of change for our function for the interval [3, 4] is -17.