Anew operating system for an existing machine is expected to cost $600,000 and have a useful life of six years. the system yields an incremental after-tax income of $155,000 each year after deducting its straight-line depreciation. the predicted salvage value of the system is $16,600. a machine costs $390,000, has a $24,500 salvage value, is expected to last eight years, and will generate an after-tax income of $60,000 per year after straight-line depreciation. assume the company requires a 12% rate of return on its investments. compute the net present value of each potential investment. (pv of $1, fv of $1, pva of $1, and fva of $1) (use appropriate factor(s) from the tables provided.)