HELP PLEASE! IM DUMB AND DONT HAVE MUCH TIME :( SPENDING 18 POINTS ON THIS

Which ahows the graph of the solution set of 6x+4y< 12

The length of the line segment joining the midpoints of sides ab and bc of the parallelogram abcd is 10. find the length of diagnol ac

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