Math Help - volume of box

1. volume of box

Hi I wonder if someone can help me, I have to show that the volume of a rectangular box is given by the foll
formula whose length is 4 metres and width is 2 metres has a and each cornes is cut away by the same amount

the formula given is V = 5x3 - 7x2 + 3x

Do I differentiate each term first and then what would be my next step?

What you've written above is difficult to understand. You have a box but you've only given it 2 dimensions. You have an $x$ in your formula but you don't say what it refers to. Can you reword things a bit more carefully. A picture would help a lot as well.