Posted by Khelany on Friday, September 6, 2013 at 11:34pm.
The length of a piece of cardboard is two inches more than its width. an open box is formed by cutting out 4 inch squares from each corner and folding the sides. If the volume of the box is 672 cubic inches, find the dimensions.

Math  Graham, Saturday, September 7, 2013 at 12:23am
Volume of rectangular prism
672 = 4*w*(w+2)
Thus:
w^2 + 2w  168 = 0
Solve for w, using quadratic formula
w = (b ± √(b^24ac))/(2a),
where
a = 1, b = 2, c = 168