Find the value of x plz

Find the area of a trapezoid with a height of 23, base 1 of 10 and base 2 of 18

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?

Is the point (0, 8) on the x-axis or y-axis? how do you know?