A box without a top is made from a rectangular piece of cardboard, with dimensions 9 m by 7 m, by cutting out square corners with side length x.

(a) What algebraic expression represents the length of the box? (In this problem, the length is the longer of the two dimensions.)
(b) What algebraic expression represents the width of the box?
(c) What algebraic expression represents the height of the box?
(d) What algebraic expression represents the volume of the box? Leave your expression in factored form.
(e) Using technology, estimate the value of x that gives the greatest volume, to the nearest tenth.