How do you know the correct order in which to evaluate algebraic expressions

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?

Write as a product: ac^2–ad+c^3–cd–bc^2+bd

Carly stated, “all pairs of rectangles are dilations.” which pair of rectangles would prove that carly’s statement is incorrect?