Help asap, which se of coordinates describe a function?

Two blends of tea are mixed to make a blend that will be sold at the fair. black tea sells for $2.20 per pound and orange pekoe tea sells for $3.00 per pound. how much of each should be used to obtain a 4lb blend selling for $2.50 per pound?

Areal estate agent earns $32,000 a year plus $1,000 for each apartment he sells. write an equation that shows the relationship between the number of apartments abe sells,n, and the total amount he earns in a year,e. what is the total amount abe would earn from selling 10 apartments in one year

Ineed to know the answer to this algebra question.