Brooks Company purchases debt investments as trading securities at a cost of $71,000 on December 27. This is its first and only purchase of such securities. At December 31, these securities had a fair value of $90,000. Brooks sells a portion of its trading securities (costing $35,500) for $40,250 cash. Analyze each transaction above by showing its effects on the accounting equation-specifically, identify the accounts and amounts (including + or -) for each transaction.