Step-by-step explanation:
Given that,
A box is created from a sheet of cardboard 40in. on a side by cutting a square from each corner and folding up the sides.
Let x represent the length of the sides of squares removed from each corner.
(a) The volume of a cuboid is given by :
V = lbh
Put values,
V = x(40-2x)(40-2x)
(b) (40-2x) = -2(x-20)
So,
V = x(40-2x)(40-2x)
= [tex]4x\left(x-20\right)^2[/tex]
(c) [tex]4x\left(x-20\right)^2=4x^3-160x^2+1600x[/tex]
It is a cubic polynomial. Its degree is 3.