Determine the continuity of piecewise function

Find the values of y: 3y^3(y^2+ 2/3y)=0

How long must $542 be invested at a rate of 7% to earn $303.52 in interest? in a easier way

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.