Butler buildings purchased semi-automated assembly and riveting robotics equipment for constructing its modular warehouse buildings. The first cost was $475,000 and installation costs were $75,000; life is estimated at 10 years with salvage value of 15% of first cost. Determine the book value after 5 years and 7 years respectively using:

(a) straight line method

(b) sinking fund method at 10%

(c) Matheson method

(d) Sum of years depreciation method.