What is x2 + 6x = x2 – 6x as a system?

a.) y = x2 + 6x
y = x2 – 6x

b.) y = –x2 + 6x
y = x2 – 6x

c.) y = –x2 – 6x
y = x2 – 6x
and can you work it out because i am so confused?

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?

What is the distance between the points (2, 5) and (5,9)?

7+(3n++8) what is the answer to this?