Assume that y varies directly with x, then solve.
If y=12 when x=15, find x when y=21.

The answer is in a fraction!
it is x = 105 / ? , I cant figure out the bottom .

The price of a particular stock is represented by the linear equation , where x represents the number of weeks the stock has been owned and y represents the price of the stock, in dollars. if this relationship continues, what is the price of the stock after it has been owned for 12 weeks? $92.55 $94.37 $100.52 $114.39

6.(q^9)^2 a. 2q^18 b. q^18 c. q^81 d.q^11 7.(6q^6)^-4 a. 6q^1296 b. 1296q^2 c. 1/1296q^24 d. 6q^-24 8. what is the value of 12x^-3 y^-1 for x = -1 and y = 5? a. -12/5 b.-10 c.-0 d.5/12

Quick! a survey of 57 customers was taken at a bookstore regarding the types of books purchased. the survey found that 33 customers purchased mysteries, 25 purchased science fiction, 18 purchased romance novels, 12 purchased mysteries and science fiction, 9 purchased mysteries and romance novels, 6 purchased science fiction and romance novels, and 2 purchased all three types of books. a) how many of the customers surveyed purchased only mysteries? b) how many purchased mysteries and science fiction, but not romance novels? c) how many purchased mysteries or science fiction? d) how many purchased mysteries or science fiction, but not romance novels? e) how many purchased exactly two types of books?