Exercise 4: A plant asset acquired on October 1, 2018, at a cost of $6,000,000 has an estimated useful life of 10 years. The residual value is estimated to be $600,000 at the end of the asset's useful life. Required: 1. Assume the company use straight-line method, calculate depreciation expense for year 2018 and 2019 and show the carrying amount as of December 31, 2018 and 2019. 2. Assume the company use double-declining-balance method, calculate depreciation expense for year 2018 and 2019 and show the carrying amount as of December 31, 2018 and 2019