What is 6b divided by 2b

The graph below could be the graph of which exponential function?

Fractions can be added and subtracted only if they're fractions. a. like b. proper c. improper d. unlike

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