year 2 3 and 4 I can't figure out for netbook value

Problem 14-57 (Algo) Compare Historical, Net Book Value to Gross Book Value, Residual Income (LO 14. 3,5) The Ste. Marie Division of Pacific Media Corporation just started operations. It purchased depreciable assets costing $90 million and having a four-year expected life, after which the assets can be salvaged for $18 million. In addition, the division has $90million in assets that are not depreciable. After four years, the division will have $90 million available from these nondepreciable assets. This means that the division has invested $180 million in assets with a salvage value of $108 million. Annual depreciation is $18 million. Annual operating cash flows are $47 million. In computing ROI, this division uses end-of-year asset values in the denominator. Depreciation is computed on a straight-line basis, recognizing the salvage values noted. Ignore taxes. Assume that the company uses a 12 percent cost of capital. Required: a. Compute residual income, using net book value for each year. b. Compute residual income, using gross book value for each year. Enter your answers in thousands of dollars.)