Give the two equations that can be solved for i with a graphing calculator to obtain the monthly interest rates corresponding to the APR and the effective mortgage rate. Assume that the loans will be held for 5 years.
1. A 15-year mortgage of $120,000 carrying a stated interest rate of 9% and one point
2. A 20-year mortgage of $150,000 carrying a stated interest rate of 6% and three points?