9. The rectangular box shown below must have a volume of 27 cubic meters. Let its base, (which is a rectangle), have length 2 meters and width y meters, and let its height be h meters where z, y and h are all positive. Use the fact that the volume of the box must be 27 cubic meters to show that 27 h= then show that the total area of its six faces is 2ry+-+ 54 54 square meters x (3) h (b) What does the nature of the critical point suggest about the area of the six faces?