(a) The monthly revenue is given by the function

, and we are given that

. So, we have

.
(b) The monthly profit is given by the function

, and we are given that

. So, we have

.
(c) We already have the formula for P(x), so you can just plug in the values:
x = 600, x = 1200, x = 1800, etc. into P(x) and write down the answers.
The trickier part is finding the derivatives. We'll start with dR/dx:
![(dR)/(dx) = (d)/(dx)[5x - 0.001x^2] = 5 - 0.002x](https://img.qammunity.org/2018/formulas/mathematics/high-school/hx5w86d310ioqf4h9kutbqq4r25pwabxr0.png)
.
The next is dP/dx:
![(dP)/(dx) = (d)/(dx)[3.5x - 0.001x^2 - 35] = 3.5 - 0.002x - 0 = 3.5 - 0.002x](https://img.qammunity.org/2018/formulas/mathematics/high-school/4jx5nzs3cabl195t8bduhkty26o32n81lw.png)
.
Once again, just plug in the different values of x into the formulas we found and we will be able to complete the table.
If you're confused on how I calculated the derivatives, let me know. I made the assumption that you already knew how to do that (although that is not always true). :)