Is this relation a function?

You paid 28.00 for 8 gallons of gasoline. how much would you pay for 15 gallons of gasoline?

Find the measure for the angle indicated in bold

One cell phone plan charges $20 per month plus $0.15 per minute used. a second cell phone plan charges $35 per month plus $0.10 per minute used. write and solve an equation to find the number of minutes you must talk to have the same cost for both calling plans.