The average rate of change formula is basically the slope formula, where you plug in: f(b)-f(a)/b-a. Then plug in the numbers. [f(0)=1,f(3)=7)]. So, 7-1/3-0. 6/3 is 2 so the average rate of change is 2. And that makes sense because the average rate of change is always the slope, and the slope is 2.