PLZZ HELP ILL GIVE BRAINLIST

Which expression is equivalent to -5(3x - 6/7)

Complete the solution of the equation. find the value of y when x equals -5. -4x - 8y = -52

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