1. \( P(t) = 45000 + 1700t. \)
2. \( P(t) = 69000 + 2500t. \)
3. \( 40 - 2n \) dollars.
4. \( 20 + 0.50n \) dollars.
5. Rate of change: 10¢ per minute. Initial value: $24 each month, independently of calls made/received.
6. Rate of change: 4¢ per minute. Initial value: $26 each month, independently of calls made/received.
7. \( f(x) = 2 + \tfrac{3}{5}(x-5) \) (or equivalent algebraic expression).
8. \( f(x) = 1 - \tfrac{1}{2}(x-5) \) (or equivalent algebraic expression).
9. \( y = 4 + 3(x-2) \) (or equivalent algebraic expression).
10. \( y = 5 + 2(x-1) \) (or equivalent algebraic expression).
11. \( y = 4 - \tfrac{1}{3}(x+1) \) (or equivalent algebraic expression).
12. \( y = 8 - \tfrac{1}{3}(x-8) \) (or equivalent algebraic expression).
13. \( y = -3 - \tfrac{3}{2}x \) (or equivalent algebraic expression).
14. \( y = 4 + \tfrac{4}{5}x \) (or equivalent algebraic expression).
15. \( y = 1 + \tfrac{2}{3}x \) (or equivalent algebraic expression).
16. \( y = 5 - \tfrac{5}{4}x \) (or equivalent algebraic expression).
17. \( p = 34 - \tfrac{1}{250}n. \)
18. \( y = 45 - \tfrac{1}{2}n. \)
19. E
20. F
21. D
22. C
23. B
24. A
25. Use a calculator
26. Use a calculator
27. Use a calculator
28. Use a calculator
29. \( (-1, 1). \)
30. \( (-2, 1). \)
31. 111.11 miles
32. If you use no more than 2500 Kilobytes.
33. (a) \( R(t) = 16 - 2.1t. \) (b) \( R(5) = 5.5 \) billion cubic feet of helium. (c) In 2017.
34. (d) \( R(t) = 1820 - 25t. \) (e) \( R(7) = 1645 \) billion barrels. (f) In 72.8 years.