The formula for any geometric sequence is an = a1 · rn - 1 , where an represents the value of the nth term, a1 represents the value of the first term, r represents the common ratio, and n represents the term number. What is the formula for the geometric sequence 4, 8, 16, 32, ...? an = 32 · 2 n - 1
an = 2 · 4 n - 1
an = 4 · 2 n - 1
an = 4 · ( ) n

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?