On Nov 1, 2017, Smith Transport traded an old diesel tractor for a new one, receiving $50 000 trade-in allowance and paying the remaining $120 000 in cash. The old tractor cost $130 000 and straight line depreciation of $90 000 had been recorded as of Nov 1 2017. Assume the fair value of the new tractor was equal to trade in value of old tractor plus the cash paid. Journalize the exchange that gave a new tractor for the old one. Journalize the amortization of a patent that cost $20 000 for a time period of ten years. Show the journal entry for the first year only for December 31