I need help answering these questions could please help with formulas

A machine costing $214,800 with a four-year life and an estimated $18,000 salvage value is installed in Luther Company's factory on January 1. The factory manager estimates the machine will produce 492,000 units of product during its life. It actually produces the following units: 121,900 in 1st year, 123,200 in 2nd year, 121,300 in 3rd year, 135,600 in 4th year. The total number of units produced by the end of year 4 exceeds the original estimatethis difference was not predicted. (The machine must not be depreciated below its estimated salvage value.)