If A, B, and C are n times n invertible matrices, does the equation Upper C Superscript negative 1 Baseline (Upper A plus Upper X )Upper B Superscript negative 1 Baseline equals Upper I Subscript n have a solution X? If so, find it.

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