Marathon Company purchased a machine for $215,695 on May 1, 2021. The machine has an estimated useful life of 7 years. The machine has an estimated residual value of $16,730. The machine is expected to be used to make 226,400 units of product over its estimated useful life. During the 2021 year, the machine is used to manufacture 42,331 units of product. Marathon Company has a September 30 year end. Required: 1. Calculate depreciation expense for the machine for the 2021 and 2022 years, assuming that the double-declining balance method is used. (2.5 marks) 2. Calculate depreciation expense for the machine for the 2021 year, assuming that the units-of-production method is used. (1.5 marks) 3. In accordance with generally accepted accounting principles, what factors should be considered in determining the method of depreciation to be used for a particular asset? (2 marks)