This is the question i hope you all could me out

Do graduates from uf tend to have a higher income than students at fsu, five years after graduation? a random sample of 100 graduates was taken from both schools. let muf be the population mean salary at uf and let mufsu be the population mean salary at fsu. how should we write the alternative hypothesis?

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?

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?