Well, my change in x would be this distance right over here. Change in x, the Greek letter delta, this triangle here, it's just shorthand for change. So change in x. And I could also calculate the change in y. So this point going up to that point, our change in y would be this right over here, our change in y. And then we would define slope, or we have defined slope, as change in y over change in x. So slope is equal to the rate of change of our vertical variable over the rate of change of our horizontal variable.