please show all work and do not use excel or a financial calculator. The answer you get must be in the answer key posted at the bottom, thanks!

5. At the end of years 2, 4, and 6, we have the following asset cash flow: A2 = 100, A4 = 200, and A6 = 300. The liability cash flow at the end of years 1, 5, and 7 is: L1 = 150, L5 = X, and L7 = 250. Asset and liability cash flows are matched in present value at an annual effective interest rate of 6.5%. (a) Calculate X. (b) Calculate the Macaulay duration of asset cash flow and liability cash flow at 6.5%. Numerical answers (in random order): 6.955, 0.062, 4.5228, 6538.49, 0.04317, 2660.67, 50000, 400.36, 202.1, 3671.29, 1951.62, 4.4621