7. You invest $300 now and $500 in four years. In exchange you will get a guaranteed payment of $200 at the end of each of the next three years, plus another payment of $400 eight years from now. (a) Write the polynomial satisfied by the discount rate v =11+i. (b) Use the Cash Flow function to solve for the effective interest rate i. (Try to get it all done with 4 entries, i.e., up to C04.)