What quadratic equation has a max of 9 and opens down

The area of a rectangle is 15+5y square feet. which of the following expressions could be the length of the sides of the rectangle, in feet a. 5 and 3y b. 5 and 3+y c. 5 and 5+y d. 3 and 5+3y

Satchi found a used bookstore that sells pre-owned dvds and cds. dvds cost $9 each, and cds cost $7 each. satchi can spend no more than $45.

16x^2-16x=5 solve the equation by completing the square