How do you find the average rate of change of f(x)=-3x to the second +7x+18

Question

How do you find the average rate of change of f(x)=-3x2 + 7x + 18, for the interval -2≤x≤1

Answer 1

That depends on the definition of the average rate of change.

You could simply take the difference between the endpoint values of f and divide by the length of the interval.

Probably better is to divide the integral of the function over the interval divided by the length of the interval.

Answer 2

Isn't it f(b)-f(a) divided by b-a ?