Find the principal invested if $624 interest was earned in 5 years at an interest rate of 5%

How can you tell when x and y are not directly proportional?

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?

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.