Joanna joins a cd club. she pays $7 per month plus ten for each cd she orders. write an inequality to find how many cd's she can purchase in a month if she spends no more than $100. identify wht your variable represents

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