Pl Help A plumber charges $55 for a service call plus $40 for each hour he works. If the total bill for a job costs $215, write an equation to represent the situation. 40 + 55 = x + 215 215 = x + 40 + 55 215 = 40 + 55x 215 = 40x + 55

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