How do you solve this problem

The sum of two numbers is 12 and their difference is 18 what are the two numbers

Vanessa earns a base salary of $400.00 every week with an additional5% commission on everything she sells. vanessa sold $1650.00 worth of items last week.

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.