I'm doing some maths homework and need some . it's pythagorean

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?

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)