What is the slope of the line that passes through point (-8,3) and (-8,2)?

In simplified exponential notation, the expression a^2•a^-3•a 1/a 0

2people are trying different phones to see which one has the better talk time. chatlong has an average of 18 hours with a standard deviation of 2 hours and talk-a-lot has an average of 20 hours with a standard deviation of 3. the two people who tested their phones both got 20 hours of use on their phones. for the z-scores i got 1 for the chatlong company and 0 for talk-a-lot. what is the percentile for each z-score?

With number 11 ( show how you got the answer)