7. (20 points) (3.1.8) A loan at rate i(12) = 0.12 is repaid with 120 monthly payments starting one month after the loan. The amount of the first payment is 600 and each subsequent payment is 5 larger than the previous payment. (5)Find The original amount of the loan. (5)Find PRI and use the result of Excercise 3.1.7 to show that PR+ = PR1(1.01)-1 +5871:(5+5)Find B&o prospectively, retrospectively, and by verifying that 0B60 = L-E, PRk, using the form of PRK found earlier in this excercise. 7. (20 points) (3.1.8) A loan at rate i(12) = 0.12 is repaid with 120 monthly payments starting one month after the loan. The amount of the first payment is 600 and each subsequent payment is 5 larger than the previous payment. (5)Find The original amount of the loan. (5)Find PRI and use the result of Excercise 3.1.7 to show that PR+ = PR1(1.01)-1 +5871:(5+5)Find B&o prospectively, retrospectively, and by verifying that 0B60 = L-E, PRk, using the form of PRK found earlier in this excercise