Ineed , it's for my exam study guide! and i'm totally lost!

What is the value of 1/3x + 7x when x = 5

Select the sequences that are geometric.

Sarah took the advertising department from her company on a round trip to meet with a potential client. including sarah a total of 11 people took the trip. she was able to purchase coach tickets for $280 and first class tickets for $1280. she used her total budget for airfare for the trip, which was $6080. how many first class tickets did she buy? how many coach tickets did she buy?