We know that f of x is equal to x to the third. And let me make it clear. This is a graph of y is equal to x to the third. And so this expression right over here, all of this, this is the slope between these two points. And as we take the limit as x approaches 5, so right now this is our x. As x gets closer and closer and closer to 5, these secant lines are going to better and better approximate the slope of the tangent line at x equals 5. So the slope of the tangent line would look something like that.