College Algebra, 4th Edition

Building Skills

1. 9. $x=4$

2. 11. $x={\displaystyle \frac{5}{3}}$

3. 13. $x=\pm {\displaystyle \frac{7}{2}}$

4. 15. $\varnothing$

5. 17. $x=1$

6. 19. $x={\displaystyle \frac{1}{2}}$

7. 21. $x=\pm 9$

8. 23. $x=10\text{,}000$

9. 25. $x={\displaystyle \frac{\text{ln }3}{\text{ln }2}}\approx 1.585$

10. 27. $x=\left({\displaystyle \frac{\text{ln }15-3\text{ ln }2}{2\text{ln }2}}\right)\approx 0.453$

11. 29. $x=-1+\text{ln }3\approx 0.099$

12. 31. $x={\displaystyle \frac{\text{ln }17-\text{ln }5}{\text{ln }2}}\approx 1.766$

13. 33. $x={\displaystyle \frac{\text{ln }10-\text{ ln }3+\text{ln }4}{2\text{ln }4}}\approx 0.934$

14. 35. $x=2+\text{ln }2\approx 2.693$

15. 37. $x={\displaystyle \frac{\text{ln }5}{\text{ln }5+\text{ln }2}}\approx 0.699$

16. 39. $x={\displaystyle \frac{\text{ln }2-6\text{ln }3}{4\text{ln }3+\text{ln }2}}\approx -1.159$

17. 41. $x={\displaystyle \frac{\text{ln }2-\text{ln }3-\text{ln }5}{\text{ln }5-\text{ln }3}}\approx -3.944$

18. 43. $t={\displaystyle \frac{\text{ln }2}{\text{ln}(1.065)}}\approx 11.007$

19. 45. $x={\displaystyle \frac{\text{ln }7}{\text{ln }2}}\approx 2.807$

20. 47. $x={\displaystyle \frac{\text{ln }2}{\text{ln }3}},{\displaystyle \frac{\text{ln }4}{\text{ln }3}}\approx 0.631,1.262$

21. 49. $x={\displaystyle \frac{\text{ln }4}{\text{ln }3}}\approx 1.262$

22. 51. $x=\text{ln }3\approx 1.099$

23. 53. $x={\displaystyle \frac{\text{ln }5-\text{ln }3}{2\text{ln }3}}\approx 0.232$

24. 55. $x={\displaystyle \frac{\text{ln }2}{\text{ln }3}}\approx 0.631$

25. 57. $x={\displaystyle \frac{\text{ln }18-\text{ln }7}{\text{ln }3}}\approx 0.860$

26. 59. $\varnothing$

27. 61. $x=-{\displaystyle \frac{49}{20}}$

28. 63. $x=3,-2$

29. 65. $x=5,2$

30. 67. $x=8$

31. 69. $x=1$

32. 71. $x=3$

33. 73. $x=4$

34. 75. $\varnothing$

35. 77. $x={\displaystyle \frac{2}{3}},{\displaystyle \frac{5}{2}}$

36. 79. $a=30,k=2;500$

37. 81. $a=5,k={\displaystyle \frac{1}{2}};31$

38. 83. $a=2,k=\text{ln }\left({\displaystyle \frac{17}{2}}\right);0.068$

39. 85. $a=-2,k=\text{ln }\left({\displaystyle \frac{11}{18}}\right);-7.902$

40. 87. $x\ge {\displaystyle \frac{\text{ln }2}{\text{ln }0.3}}$

41. 89. $x\le 0$

42. 91. ...