Math !
explain when is a rational expression restricted.

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

Jack brought 12 pet monkeys. if each monkey cost $45.99, how much money did he spend in all?

Un used xx milliliters, or 90\%90%, of his favorite bottle of hot sauce. which of the following expressions could represent the volume of a full bottle of jun's favorite hot sauce, in milliliters? choose 2 answers: choose 2 answers: (choice a) a \dfrac{x}{0.9} 0.9 x (choice b) b \dfrac{10}{9}x 9 10 x (choice c) c 0.9x0.9x (choice d) d xx (choice e) e x+0.1x+0.1