Calculate the average rate of change of a function over a specified interval.

Which expression can be used to determine the average rate of change in f(x) over the interval 2, 9?

On a coordinate plane, a curve opens down and to the right. The curve starts at (0, 0) and goes through (1, 3), (4, 6), and (7, 8).
f(9 – 2)
f(9) – f(2)
StartFraction f (9 minus 2) Over 9 minus 2 EndFraction
StartFraction f (9) minus f (2) Over 9 minus 2 EndFraction