I don’t understand this question

If f(x) = x+8 and g(x) = 4x- 3, find (f+g)(x)

Mason and christian go to the movie theater and purchase refreshments for their friends. mason spends a total of $45.75 on 3 bags of popcorn and 6 drinks. christian spends a total of $71.50 on 6 bags of popcorn and 4 drinks. write a system of equations that can be used to find the price of one bag of popcorn and the price of one drink. using these equations, determine and state the price of a drink, to the nearest cent.

Five friends found a dollar on the ground and decided they each should get 1/5 of it. what amount of money will each friend get? $0.05 $0.20 $0.30 $0.80