The average rate of change of a function f(x) = x2 between x = 3 and x = 9 is
average rate of change =

12.

Step-by-step explanation:

Average rate of change = (value of the function when x = 9 - value when x=3)

/

(9 - 3)

= f(9) - f(3) / (9-3)

= (9^2 - 3^2) / (9-3)

= 72 / 6

=  12.