An open box with locking tabs is to be made from a squre piece of cardboard with side length 36cm. This is to be done by cutting equal squares of side length x centimetres from the corners and folding along th dotted lines as shown. A polynomial function that represents the volume, V, of the box is: V(x) = 8x(18-x)(9-x). Determine the maximum volume of the box. What is the value of x for the box with max volume? give your answers to the nearest tenth.