I need the equation for the volume.

V Ala-in ~by724n sheet of cardboard Is folded In half to form a 42- -.In -by-36-' In. rectangle as sh accompanying gure. Then four congruent squares of side length x are cut from the come The sheet is unfolded. and the six tabs are folded up to form a box with sides and id Co below. 42 In- . [1 72in. >| || k'72in. ->|