What’s the inequality and solve and graph

Pls never taught i’m really confused and i rlly need

Frank has a devised a formula for his catering business that calculates the number of meatballs he needs to prepare. the formula is m=4a+2c, where c=number of children; m=number of meatballs; a=number of adults. how many meatballs are required for a party of 10 adults and 5 children?

Eden has a part time job. she is paid ? 7.20 an hour the week she worked 18 and a half hours how much is she paid