First we need to find f(2) and f(5), which are 5 and 11 respectively; all you have to do is plug in 2 and 5.
Then, we use the following formula:
(f(b)-f(a))/(b-a),
where b and a are the largest and smallest x values respectively.
Finally, we plug our values in:
(11-5)/(5-2)=6/3=2
In fact, the average rate of change of any linear function is just the coefficient of the x term. Hope this helped!
