So this is essentially the area under f of t, or under f of x, if you wanna view it that way, from zero to three. And this is pretty straightforward to figure out, but we have to be careful here. Because this area, this area right over here, this would be the integral, let me do this in a color that you can see, that area right over there would be the integral from negative three to zero, f of t, or we could either say f of t dt, or f of x dx, either way, dt. That would be this area right over here. They've swapped it. They have the larger number as the lower bound. They have zero as the lower bound.