G = {(0, 1)} Is G-1 a function and why?

The parabola x = y² - 9 opens: a.)up b.)down c.) right d.)left

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)

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?