Lincoln bought 3 bottles of energy drink for $4.50. wrote an equation relating the total cost y to the number of energy drinks bought x.

The parabola x = y² - 9 opens: a.)up b.)down c.) right d.)left

Find the equation using the point (4,8)

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! )