12. (3 points) A box with no top is being made out of an 18-cm by 24-cm piece of cardboard by cutting equal squares of side length x from the corners and folding up the sides. 24 cm 18 cm The volume of the box is given by the equation (x) = x (18-2x) (24-2x). Determine the volume if the side length of each square cut is 3 cm. a. 468 cm b. 648 cm C. 720 cm d. 1020 cm