Please help me in Part C, show the result to understand the part (thanks)

11-51 A computer costs $3500 and its salvage value in 5 years is negligible. What is the book value after 3 years? If the machine is sold for $1500 in Year 5, how much gain or recaptured depreciation is there? Assume (a) Straight-line depreciation (b) Double declining balance depreciation (c) 20% bonus depreciation with the balance using 5-year MACRS