6 ÷ 10 I need help show my work and knowing the answer

Show algebraically that f and g are inverse functions f(x)=x^2/-6; g(x)=square root of 2x+12

What is f(3) for the quadratic function f(x)= 2x^2+ + x - 12

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?