Lambert Company acquired machinery costing $110,000 on January 2, 2019. At that time, Lambert estimated that the useful life of the equipment was 6 years and that the residual value would be $15,000 at the end of its useful life. Compute depreciation expense for this asset for 2019, 2020, and 2021 using the

a. straight-line method.

b. double-declining-balance method.

c. Assume that on January 2, 2021, Lambert revised its estimate of the useful life to 7 years and changed its estimate of the residual value to $10,000. What effect would this have on depreciation expense in 2021 for each of the above depreciation methods?