19. What is the annual rate of interest required to triple an investment in 5 years if the interest is quarterly? Answer to the nearest hundredth of a percent. [2 marks] 20. If log n =-5 and x = p determine the exact value of log, (n) - log,(x) . [4 marks] 21. Solve the following expressions algebraically. Do not use technology. [2 marks each] a) 21085x = 3logs() b) log,x + log,3 = log, 15 c) - log, (x - 1) = log,(x + 3) - 5