Postal Restrictions If a box with square cross section is to be sent by the postal service, there are restrictions on its size such that its Volume is given by V= x²(108-4x), where x is the length of each side of the cross section (in inches).
(a) Is V a function of x?
(b) If V= V(x), find V(10) and V(20).
(c) What restrictions must be placed on x (the domain) so that the problem makes physical sense?