The price for apples is $3.50 times the number of apples bought plus one-dollar tax. if martin bought 3^3 amount of apples. how much did the apples cost?

Me because some of question i don’t understand

The serenity and the mystic are sail boats. the serenity and the mystic start at the same point and travel away from each other in opposite directions. the serenity travels at 16 mph and the mystic travels at 19 mph. how far apart will they be in 3 hours?

Which equation is y = -6x2 + 3x + 2 rewritten in vertex form?