A pair of jeans are originally $39.50 and are 15% off. The sales tax is 7%. After the discount and tax, how much will the total be ? A) $6.34
B) $7.82
C) $30.81
D) $35.93

Me because some of question i don’t understand

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.

Line u passes through points (-52, -18) and (-29, 53). line v passes through points (90, 33) and (19, 56). are line u and line v parallel or perpendicular?