Equipment costing $$72,000$ with a $4-$year useful life and an estimated $$12,000$ salvage value is acquired and started operating on January $1.$ The equipment is estimated to produce $5,000$ units of product during its life. It produced $750$ units in the first year. Record the journal entries for equipment depreciation for the first year under straight$-$line, units$-$of$-$production, and double$-$declining$-$balance.