Audrey charges 4$ per hour to babysit. if x represents the number of hours that she babysits which expression represents how much she will earn babysitting

How do i do this activity, is appreciated

Monitors manufactured by tsi electronics have life spans that have a normal distribution with a standard deviation of 1800 hours and a mean life span of 20,000 hours. if a monitor is selected at random, find the probability that the life span of the monitor will be more than 17,659 hours. round your answer to four decimal places.

Let x = a + bi and y = c + di and z = f + gi. which statements are true?