Answer
It was 11 by 14 inches
Work Step by Step
We know:
$ l = w+3$
Since 2 inch squares are cut off each side, we know that the length and width of the cube are each 4 less than the length and width of the rectangle, and we know that the cube's height is 2. (Recall, width can't be negative.) Thus:
$ V = lwh \\ 140 = (w+3)(w)(2) \\ 0 = 2w^2 +6w - 140 \\ (2)(w-7)(w+10) \\ w =7 $
Since the width of the original cardboard is 4 inches longer, its width is 11 inches. This means that the original length is 11 +3 = 14 inches.
