So right over here we have the graph of y is equal to x squared, or at least part of the graph of y is equal to x squared, and the first thing I'd like to tackle is think about the average rate of change of y with respect to x over the interval from x equaling one to x equaling three. So let me write that down. We want to know the average rate of change of y with respect to x over the interval from x going from one to three, and it's a closed interval where x could be one and x could be equal to three. Well we could do this even without looking at the graph. If I were to just make a table here where if this is x and this is y is equal to x squared, when x is equal to one, y is equal to one squared, which is just one. You see that right over there. And when x is equal to three, y is equal to three squared, which is equal to nine.