Can you provide me with step by step explanation

If a company produces x units of an item at a cost of $35 apiece the function c=35x is a of the total production costs

Aright cylinder has a diameter of 8 m and a height of 6m. what is the volume of the cylinder

Three students, javier, sam, and corrine, participated in a fundraiser where people donated a certain amount of money per lap that the student ran. each student also had some initial donations that were collected before the run. the equations that represent each student's total donation, y, based on the number of laps ran, x, is shown below. match each equation with the correct rate of change for that student.