Help me figure out what to divide by 18

Fredrick designed an experiment in which he spun a spinner 20 times and recorded the results of each spin

What is the equation of this graphed line? enter your answer in slope-intercept form in the box.

Barney & noblet customers can choose to purchase a membership for $25 per year members receive 10% off all store purchases 1. how much would a member pay per year if he bought $50 worth of items each year? 2. write a slope-intercept equation that expresses how much a member pays per year using x to represent his purchases per year 3. how much would a member have to spend per year to pay off his membership fee?