Y = 2x + 6. If x = 5, how much is y?

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

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

Can someone me out here and the tell me the greatest common factor