How do I get the y-coordinates?

If the class was going to get a class pet and 5 picked fish and 7 pick bird and 8 picked rabbits have many students were in the

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?

What is the point of inflection for the function f(x)=2cos4x on the interval (0, pi/2)