Find the solution to the system by graphing. x+y=0 2x-y=-9

Two parallel lines are crossed by a transversal.what is value of x

The formula for the lateral area of a right cone is la = rs, where r is the radius of the base and s is the slant height of the cone.which are equivalent equations?

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