Calculate the annual depreciation expense for a piece of machinery purchased by IBM.

Item	Amount ($)
Cost of Machinery	600,000
Salvage Value	60,000
Useful Life	8 years
Depreciation Method	Double-Declining Balance

Question:

Using the given data, calculate the annual depreciation expense for the machinery using the double-declining balance method for the first two years. Show your calculations and explain the rationale behind using the double-declining balance method.