1. The problem statement, all variables and given/known data I have just started my first ever calculus course, and I'm having a little trouble with a simple rate of change problem. It says: Find the average rate of change of the given function between the following pairs of x-values. The given function is f(x) = x2+ x The given values are x=1 and x=3 2. Relevant equations Aren't I supposed to make use of the equation f(x+h) - f(x) / h ? I don't really understand what h is supposed to be. 3. The attempt at a solution I checked what the answer should be and it shows: f(3) - f(1) / 2 = 12-2 / 5 = 5 I understand the algebra and how it equates to the answer 5, but where did the two in the denominator come from? I feel like I'm not understanding some fundamental aspect of this problem and rates of change in general.