Recording transactions involving tangible and intangible assets. Present journal entries for each of the following transactions of Moon Macrosystems:

a. Acquired computers costing $\$ 400,000$ and computer software costing $\$ 40,000$ on January 1, Year 6. Moon expects the computers to have a service life of 10 years and $\$ 40,000$ salvage value. It expects the computer software to have a service life of four years and zero salvage value.

b. Paid $\$ 20,000$ to install the computers in the office. Paid $\$ 10,000$ to install and test the computer software.

c. Recorded depreciation and amortization using the straight-line method for Year 6 and Year 7. Moon records a full year of depreciation in the year of acquisition. Treat depreciation and amortization as a period expense.

d. On January 1, Year 8, new software offered on the market made the software acquired above completely obsolete. Give any required journal entry.

e. On January 2, Year 8, Moon revised the depreciable life of the machines to a total of 14 years and the salvage value to $\$ 56,000$. Give the entry to record depreciation for Year 8.

f. On December 31, Year 9, Moon sold the machines for $\$ 260,000$. Give the required journal entries for Year 9 .