Questions 6-9 I can't figure out the equations that go with these. I'd appreciate a step by step walkthrough. Thank you so much!!

[2010) (61) (121) + zoo] -Y = 59528. 6. If you invest $2.000 a month for 20 years at 6%, find the present value. (3) 7. If a person invests at 10% compounded annually, how long will it take the principal to quadruple? (3) 8. The current population of Giles is 5,000 people, with a growth rate of 3% per year. The current population of Selig is 6,000 people, with a growth rate of 2% per year. How many years will it take before Giles becomes larger than Selig? (4) 9. Suppose you are offered $10,000 at the end of five years. If you can invest at 10% compounded continuously, how much would you have to be offered today to be of an equivalent value to the other offer? (3)