a) M(t) = (9000)(1.03)^t
b) a = $9,000, which represents the initial deposit of money
c) b = 1.03, which represents the growth of money (1 + 3% = 1.03) each year
d) After 3 years, t = 3, so M(t) = (9000)(1.03)^3 = $9,834.54
e) We need to find when M(t) = 15000:15000 = 9000(1.03)^t5/3 = (1.03)^tt = ln(5/3) / ln(1.03) = 17.28 years ~ 18 years.