3x+7=8x+7

a. infinite solutions
b. one solution
c. no solution

Can some one me with these questions

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?

Calculate the missing value. round the answer to on decimal place. start with 70, increase it by 21%, and end up with