Anyone know?

Question 101 points)which equation in slope-intercept form represents the line that passes through (5, 1) and(-4,7)

Determine whether the set of whole numbers is closed under addition. explain why the set is or is not closed. give an example.

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?