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The multiplication property of zero states that the product of any number and 0 is 0. what must be true about either a or b to make ab=0

Which expression is equivalent to the expression shown?

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?