One safe investment pays 10% per year and a more risky investment pays 18% per year. A woman has $145,600 to invest and would like to have an income of $20,000 per year from her investments. How much should she invest at each rate? a.) Write the necessary equations. b.) Convert the equations to coefficient and variable matrices. c.) Solve this problem using inverse matrices and find the inverse using the Gauss-Jordan Method. d.) How much should she invest at each rate.