Find the missing side length

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?

Does the point (1, sqrt 7) lie on circle shown.

In terms of x, find an expression that represents the area of the shaded region. the outer square has side lengths of (x+5) and the inner square has side lengths of (x-2), as shown. area: a1 x + a2 square units submit