MORE POINTS FIRST TO ANSWER GETS BRAINLEST

Use the elimination method to solve the systems of equations.choose the correct ordered pair. 7x+4y=39

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.

Divide. –40 ÷ –5 a –8 b 200 c -200 d 8