E9-7 Mactaquac Company purchased a piece of high-tech equipment on July 1, 2 016, for $30,000 cash. The equipment was expected to last four years and has a residual value of $4,000. Mactaquac uses straight-line amortization and its fiscal year end is June 30. On July 1, 2017, Mactaquac purchased and installed a new part on the equipment which is expected to increase the equipment's productivity a lot. Mactaquac paid $5,000 cash for the part. It paid an additional $500 for the installation and testing of this part. The equipment is expected to last six years in total now and has a revised residual value of $3,000. Instructions (a) Record the annual amortization of the equipment on June 30,2017 (b) Record the purchase of the part, and its installation and testing, on July 1, 2017 (c) Record the annual amortization of the equipment on June 30, 2018 (d) Calculate the net book value of the equipment on June 30, 201g , after recording the annual amortization