Pls help quick number 2 and 3 pls!

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?

Aquadratic equation in standard from is written ax^2= bx+c, where a, b and c are real numbers and a is not zero?

The roots of the function f(x) = x2 – 2x – 3 are shown. what is the missing number?