For each of the following cases, respond to the question asked and indicate the accounting principle or concept that applies. 1. Sanchez Company has decided to charge off as a loss the portion of its accounts receivable that it estimates will be uncollectible. The accounts involved resulted from the current year's sales. Is this correct or incorrect accounting? Why? 2. On March 15 of last year, Zane Inc. purchased land for $420,000, on which it planned to construct an office building. At the end of the year, the land had increased in value to $520,000. Nevertheless, Zane recognized no income as a result of the increase in value. Is this correct or incorrect accounting? Why? Page 533 3. Three years ago, Williamson Company purchased a machine for $600,000. The machine is expected to have no salvage value. Nevertheless, Williamson continues to keep the asset's cost in its accounting records and to depreciate the asset over its 10-year useful life. Is this correct or incorrect accounting? Why