If 10 apples cost $1 how much would it cost per Apple

Solve the system of equations. y= 2x y= x^2 - 15

Write the point-slope form of the line passing through (2, -12) and parallel to y=3x.

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