Ahmad has been approached by his two friends who are the salesmen from two banks, Bank A and Bank B. Ahmad has been asked to make some investment in his friend's bank. Ahmad plan to invest RM 3500. Bank A will give an annual return of 7.1% with a yearly fee of RM 98 for its services. Bank B will give an annual return of 5.2 % with a yearly fee of RM 55 for its services. a. By letting y to represent the return value of investment made by Ahmad at time x, create a first order differential equation to represent the change in Ahmad money over time for both Bank A and Bank B respectively. Then, solve the equations by using an integrating factor. [15 marks] b. Explain whether the two banks are offering a good investment for Ahmad. Justify your answer by using equations, tables, graphs, etc. [10 marks]