A Machine Cost $21,000 and Has an Estimated Useful Life

A machine cost $21,000 and has an estimated useful life of five years and a residual value of $3,000. What is the annual amortization expense for each of the first two years under the following amortization methods? $\begin{array}{|l|l|l|}\hline & \text { Year } & \text { Year } \\& 1 & 2\\\hline \text { (a) Sum-of-the-years'-digits } \\\hline \text { (b) Declining balance } & \$ & \$ \\\hline \text { (c) Productive output (potential output is estimated at 90,000 units, in the first year, the machine turned } & \$ & \$ \\ \text { out } 15.000 \text { units, in the second year. } 18.000 \text { units) } & \\\hline \text { (d) Straight line } & \$ & \$ \\\hline\end{array}$