Final answer:
The expression to describe the length of the original board after a 4-foot cut is 'x - 4' feet, with x representing the initial length of the board.
Step-by-step explanation:
To find an expression that describes the length in feet of the original board after a 4-foot cut, you would subtract the length of the piece cut from the total length of the board. If the board was originally x feet long, then the length of the board after making the cut is: x - 4 feet. This expression accounts for the reduction in the length of the board after removing 4 feet.