please explain and answer example 3 & 4

Example 3: (a) ABC Loans lends money to college students with a nominal interest rate of 9% compounded monthly. What is the effective annual interest rate of a student loan? (b) DEF Loans lends money to college students with a monthly interest rate of 0.8%. What is the effective annual interest rate of a student loan? Example 4: Your credit card company charges a nominal 19.99 percent interest on your over-due accounts, compounded daily. What is the effective interest rate