Question:

An open-top box is to be contructed from a piece of cardboard by cutting congruent squares from the corners and then folding up the sides.
I have already figured out the rest of the questions pertaining to.. except for the last part:

D) Using your function V= x(32-2x)(40-2x);
determine the values of "x" that will result in boxes with a volume greater than 2016 cm^3

2. Solve $x(32-2x)(40-2x)> 2016$

3. thanks for answering.. but more specifically?

my teacher is clueless and im trying to learn this on my own..

i have the answer as " apprx. 2 < x < 10.9 or x >23.1 "

but i dont know how to get there

Note that $x(32-2x)(40-2x) - 2016$ can be factorised as $4(x - 2) (x^2 - 34x+252)$ so you should be able to exactly solve $x(32-2x)(40-2x) - 2016 = 0$. A rough sketch graph of $y = x(32-2x)(40-2x) - 2016$ can then be used to solve the required inequality.