Write an expression to describe the sequence below. Use n to represent the position of a term in the sequence, where n = 1 for the first term. –4, –8, –12, –16,

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )