Bridgeport Inc. makes unfinished bookcases that it sells for $59. Production costs are $38 variable and $10 fixed. Because it has unused capacity, Bridgeport is considering finishing the bookcases and selling them for $71. Variable finishing costs are expected to $8 per unit with no increase in fixed costs. Prepare an analysis on a per-unit basis that shows whether Bridgeport should sell unfinished or finished bookcases. (If an amount reduces the net income then enter with a negative sign preceding the number, eg. 15,000 or parenthesis, eg. (15,000).)