Question

A box is created from a sheet of cardboard 20 in. on a side by cutting a square from each corner and folding up the sides. Let x represent the length of the sides of the squares removed from each corner. Find an expression for the volume of the box in terms of x

Answer 1

assuming the sheet is a square

see diagram
the length will be 20-2x
the width will be 20-2x
and the height will be x

the volume will be (20-2x)(20-2x)(x)