What is the 7th, 8th and 9th step of the derivation of the quadratic formula?

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?

Can someone me with these two circle theorem questions asap?

What is the solution to the equation below? 3/x-2+6=square root x-2 +8