The sum of three numbers is 18 but every number is prime

Find dy/dx using implicit differentiation ln(20+e^xy)=y

Consider the graph of the exponential function y=3(2)×

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?