Lambert Company acquired machinery costing 110,000 on january 2nd 2016 at that time lambert estimated the useful life of the equipment was 6 years old and the residual value would be 15,000 at estimated the end of its useful life. Compute depreciation expense for this asset for 2016, 2017, 2018 using

a) straight line method

b) double declining balance method

c) assume that on Jan 2nd 2018 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 2018, for each of the above depreciation methods?