Movie mania requires customers to pay a sign-up fee of $20, and charges $4.00 to rent a dvd. hurricane video is free to join, but dvds cost $6.00 to rent. write and solve an equation to find the number of dvds you would have to rent in order for both stores to charge the same. explain what your variable represents. answer choices in picture.

Apinhole camera is made out of a light-tight box with a piece of film attached to one side and pinhole on the opposite side. the optimum diameter d(in millimeters) of the pinhole can be modeled by d=1.9[ (5.5 x 10^-4) l) ] ^1/2, where l is the length of the camera box (in millimeters). what is the optimum diameter for a pinhole camera if the camera box has a length of 10 centimeters