Subassemblies for a product are purchased for $$71$ a piece. The annual demand is

$350$ units and is expected to continue for $3$ years at which the product is ready for

manufacturing with the equipment purchase and installed for $$21,000,$ the

production costs to internally produce the subassemblies should be $$18,500$ for

the first year and $$12,250$ each of the last two years. The equipment has no

salvage value. Should the company make or buy the assemblies? Show steps on paper then how to find with excel please. Explain and show each step and equations used