A machine purchased three years ago for $$800,000$ has a current book value using straight$-$line depreciation of $$300,000$; its operating expenses are $$70,000$ a year. A replacement machine would cost $$600,000,$ have a useful life of nine years, and would require $50,000$ per year in operating expenses. It has an expected salvage value of $$200,000$ after nine years. The current disposal value of the old machine is $$275,000$; if it is kept $9$ more years, its residual value would be $$75,000.$ No credit will be given unless you show all you work$).$

Based on this information, should the old machine be replaced? Explain and support your work.