SOLVE PLEASE REALLY NEED HELP
4√n^2 + √m^2n - √4n^2 - √mn^2

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.

An 18% discount on a watch saved a shopper $72. find the price of the watch before the discount

How do i simply this radical expression?