Afootball player starts on the 20 yard line and gains 9 yards. on the next play, he loses 4 yards. the referee says there���s a penalty and takes away the 4-yard loss of yardage. which expression represents the total number of yards gained?

What were mkh company's cash flows from (for) operating activities in 20x1? $(180,300) $233,100 $268,200 $279,400?

Which of the following contains a variable?

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