Can someone please help me with these questions

F(n + 1) = f(n) – 8. if f(1) = 100, what is f(6)?

Aclothing designer is selecting models to walk the runway for her fashion show. the clothes she designed require each model’s height to be no more than y inches from 5 feet 10 inches, or 70 inches. which graph could be used to determine the possible variance levels that would result in an acceptable height, x?

Tom travels between the two mile markers shown and then finds his average speed in miles per hour. select the three equations that represent this situation.