Which of the following methods might involve having a specific population answer a questionnaire?

The system of equations graphed below has how many solutions? y = 2x + 2

Divide. write in the simplest form. 4 1/6 divided by 10

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