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. Capital F of a is just literally the area between c and a under the curve, lowercase f of t. So it's this right over here. It's all of this business, all of this right over here. So what is, if you have this blue area, which is all of this, and you subtract out this red, this magenta area, what are you left with?