A restaurant charges $20 for a main meal and $2.50 for any optional extra. Write an algebraic expression for the cost of main meals and optional extras.
Ethan went to the park with his family and bought 6 bottles of coconut water for each and a large bag of organic potato chips for $3.40. Write an expression in the simplest form that represents the total amount of money he spent.
Write two algebraic expressions involving multiplication that have the same meaning.