HELP!!! MATH!!! Can't figure out this question!!?

Question

A box with an open top is to be constructed from a rectangular piece of
cardboard with
dimensions 12 inches by 20 inches by cutting out equal squares of side x
at each corner
and then folding up the sides. Express the volume V of the box as a
function of x.

Answer 1

OK -you're going to cut 4 squares, one from each corner of a 12 X 20 sheet. The length of the side of the cutout is X.

The 12 inch side will have a square cut off each end, so the length left will be 12 - 2X.

Same for the 20 inch side - it will be 20 - 2X.

Now, when you fold up those flaps you made, the depth of the box will be X , the cutout.

So volume will be L*W*D, or

(12-2X)(20-2X)(X) = V

Answer 2

If you cut out squares and fold up the sides, you will get an open box. You cut out two squares from each side, so the bottom of the box would be (12 - x) inches by (20 - x) inches. The box's height will be x.
Volume = lwh (length times width times height)
Plug in the expressions:
V = (12 - x) (20 - x) (x)
You can multiply this out to get V = x^3 - 32x^2 + 240x

This question is a lot easier if you draw a picture.