Please help me I don't know what I am doing and if someone could explain or teach me, I would really appreciate it. :(:

If f(x)= 3x+6 which of the following is the inverse of f(x)

Add the two expressions 3.8b - 7 and 2.9b + 9 enter your answer in simplified form

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?