ACME Company purchased equipment on January 1, 2007, at acost of $180,000. The equipment is expected to have a useful lifeof four years or 10,000 units and have a residual value of $18,000.During 2007, the equipment produced 4,000 units. Determine thedepreciation expense for 2007 under the (a) straight-line, (b)double declining balance, and (c) units-of-production methods.