Computer Consultants purchased a building for $450,000 and depreciated it on a straight-line basis over 40 years. The estimated residual value was $93,000. After using the building for 20 years, Computer realized that the building would remain useful only 14 more years. Starting with the 21 st year, Computer began depreciating the building over a revised total life of 34 years and decreased the residual value to $18,100. Requirement 1. Record depreciation expense on the building for years 20 and 21. (Record debits first, then credits. Exclude explanations from any joumal entries.) Start by recording depreciation expense on the building for year 20