What are some ways in which the structure of a compound influences its function?

Jaxon bought a cell phone. A cell phones down payment is $35. There is a monthy cost $20. A. Write an equation that gives the total cost ( in dollars ) of paying a down payment for a cell phone and paying a monthly payment as a function of the number of months needed to pay off the phone in full. Write the equation in slope form. .

y=m x +b =