My question for problem down below comes from when I need to use an economic function and when I don't. I am getting very confused. Not only that, but when I see the function such as the below C(x)= 5250 + 7.00x and I see I need to substitute or find C(300), I become very clueless and do not know what to do. Please help me with this step by step problem going through all the steps so I know how you go to the answer. I have a few other similar questions, I need to be able to manage this on my own hopefully without saying this.

Question: All questions will use an economic function

The cost, in dollars, for a company to produce a widgets is given by C(x)= 5250 +7.00x for x> or = to 0, and the price- demand function, in dollars per widget, is p(x)= 45 - 0.02x for 0 < or = to x < or = to 2250.

(a) Can you help me find and interpret C(300).

(b) On this question it says the C(x) is the average cost function. I am not sure what that means. It's asking to find and interpret C(300) again with the not of the average cost function. Economic functions are not my strong foot.

(c) For this question I don't understand how to find and simplify the expression for the revenue function R(x). I don't understand economic functions.

(d) It say to find and simplify the expression for the profit function P(x). While there is a note stating that p(x) and P(x) ARE in fact different functions, that does not help me at all with this problem. I am hoping maybe this means something to you with economic functions.

(e) This question has to do like the above question. It says to find and interpret P(300), where P(x) is the profit function in part (d).

All help is much appreciated. Thank you!