How do you figure out if functions are inverses or not

14. (05.02 lc) what is the value of y in the solution to the following system of equations? (5 points) 2x + y = −4 5x + 3y = −6

Write an equation for the function that includes the points (1,4/5) and (2,2/3)

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