Can someone help me plz

Combine like terms to make a simpler expression 3z+z

Write the equation in logarithmic form e^x=403.429

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.