Can someone tell me the steps to solving this problem?
5x - 15 + 3^2= 40

When using the linear combination metho e linear combination method to solve a system of linear equations, the four options are:

Over the last 8 nights, elyse earned the following in tips: {105, 120, 84, 95, 100, 132, 140}. if she earns $140 a night for the next four nights, which measure of center would increase more, the mean or median?

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