I need help. i don’t understand

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?

Cos^2x+cos^2(120°+x)+cos^2(120°-x)i need this asap. pls me

How do u write a function for the reflection across the y axis