3(x−1)=15

what is x and how did you get it i need help pleasee

Find three consecutive numbers such that the sum of one-fourth the first and one-fifth the second is five less than one-seventh the third

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

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?