"John puts $200 in his safe and starts saving $50 per month. Write a function rule for the amount of money he will have in his safe after x months. How much money will be in his safe after 12 months?"
I got how much money will be in his safe after 12 months, but I don't understand how to write a function for it.
x: amount of time, in months
f(x): amount of money as a function of time
f(x) = 200 + 50x