Iam going to freaking kill myself if no one me with my questions

7.=7.6

a.
–7.6

b.
–1

c.
0

d.
1

what is the value of the expression?

2/3-(1//9)

a.-5/9

b.-1/6

c.1/6

d.5/9

what is the value of the expression?

-3+)

a.
–31

b.
–16

c.
16

d.
31

you xoxox

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.