Write an expression to show how much it costs per week to keep the 8 adults where x is the number of pounds one adult eats in a day. Simplify your expression. PL I NEED HELP ASAP

Kayla made observations about the sellin price of a new brand of coffee that sold in the three different sized bags she recorded those observations in the following table 6 is $2.10 8 is $2.80 and 16 is to $5.60 use the relationship to predict the cost of a 20oz bag of coffee.