 So to find the area bounded by y equals x squared, the x-axis, x equals 1, and x equals 3, the first thing we should do is graph the region, and very importantly, we should label. So here we have x equals 1, x equals 3, and y equals x squared. Now, since we want to find the area, it helps to draw that representative rectangle. And this rectangle has height y and dx, so the area is going to be y dx. We want to sum these areas, and remember the differential variable is controlling. Everything has to be in terms of x. So our x values run from x equals 1 up to x equals 3. And again, everything has to be in terms of our differential variable x, and we know that y is equal to x squared. So equals means replaceable, and so instead of y, we'll write x squared. Now we can find our anti-derivative, include our limits of integration, and evaluate upper limit minus lower limit.