Question: Ally has a monthly movie ticket subscription. For a monthly fee, she can watch
 any one movie of her choice at any time. For any additional movies that she
 watches, she pays a discounted price. The equation below represents the situation
 where y is the total monthly subscription cost based on x, the number of
 additional movies watched.
 y = 6.5x + 7.99
 Which statement is the best interpretation of the rate of change?