What is the constant proportionality in this relationship?

Plzzzz i beg u asap ! what is the equation of this graphed line? enter your answer in slope-intercept form in the box.

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?

Put the equation in slope intercept form by solving for y