On January $2,2017,$ Wavepoint Systems, a cell phone manufacturer, installed a computerized machine in its factory at a cost of $$168,200.$ The machine$$s useful life was estimated at four years or a total of $189,600$ units with a $$26,000$ trade$-$in value. Wavepoint$$s year$-$end is December $31.$

Calculate depreciation for each year of the machine$$s estimated useful life under each of the following methods:

a$.$ Straight$-$line

b$.$ Double$-$declining$-$balance

c$.$ Units$-$of$-$production, assuming actual units produced were:

$201739,000$

$201842,200$

$201953,300$

$202063,000$