So let's say that b is this right over here. Let me do that in the same color. So let's say that b is right over here. F of b is going to be equal to, we just literally replaced the b where you see the x, it's going to be equal to the definite integral between c and b of f of t, dt, which is just another way of saying, it's just another way of saying is the area under the curve between c and b. So this f of b, capital F of b, is all of this business, all of this business right over here. And from that, we are going to want to subtract, we are going to subtract capital F of a, which is just the integral between c and lowercase a of lowercase f of t, dt. So let's say that this is, let's say that this is a right over here.