Practice and Problem-Solving Exercises

A Practice

See Problems 1 and 2.

Solve each equation using addition or subtraction. Check your answer.

10. 6 = x + 2
11. 27 + n = 46
12. 23 = v + 5
13. 4 = q + 13
14. f + 9 = 20
15. − 5 + a = 21 negative 5 plus eh equals 21
16. − 17 = 3 + k negative 17 equals 3 plus k
17. 5.5 = − 2 + d 5.5 equals negative 2 plus d
18. c + 4 = − 9 c plus 4 equals negative 9
19. 67 = w − 65 67 equals w minus 65
20. 23 = b − 19 23 equals b minus 19
21. g − 3.5 = 10 g minus 3.5 equals 10
22. y − 19 = 37 y minus 19 equals 37
23. q − 11 = − 9 q minus 11 equals negative 9
24. − 2.5 = p + 7.1 negative 2.5 equals p plus 7.1
25. j − 3 = − 7 j minus 3 equals negative 7

See Problems 3 and 4.

Solve each equation using multiplication or division. Check your answer.

26. − 8 n = − 64 negative 8 n equals negative 64
27. − 7 y = 28 negative 7 y equals 28
28. 5b = 145
29. 6a = 0.96
30. − 96 = 4 c negative 96 equals 4 c
31. 11 = 2.2t
32. 17.5 = 5s
33. 7 r = − 7 2 7 r equals , negative , 7 halves
34. m 7 = 12 m over 7 , equals 12
35. 35 = j 5 35 equals , j over 5
36. k 7 = 13 k over 7 , equals 13
37. − 39 = q 3 negative 39 equals , q over 3
38. 14 = z 2 14 equals , z over 2
39. q − 9 = − 9 q over negative 9 , equals negative 9
40. − 13 = m − 5 negative 13 equals , m over negative 5
41. k 4 = − 17 2 k over 4 , equals negative , 17 over 2

See Problem 5.

Solve each equation. Check your answer.

42. 2 3 q = 18 2 thirds , q equals 18
43. 3 4 x = 9 3 fourths , x equals 9
44. 5 8 y = − 1 5 eighths , y equals negative 1
45. 3 5 m = − 15 3 fifths , m equals negative 15
46. 1 5 x = 2 7 1 fifth , x equals , 2 sevenths
47. 36 = 4 9 d 36 equals , 4 ninths , d
48. − 6 = 3 7 n negative 6 equals , 3 sevenths , n
49. 3 8 p = 9 3 eighths , p equals 9

See Problem 6.

Define a variable and write an equation for each situation. Then solve.

50. Music You have a rack that can hold 30 CDs. You can fit 7 more CDs on the rack before the rack is full. How many CDs are in the rack?
51. Population In a 3-year period, a city's population decreased by 7525 to about 581,600. What was the city's population at the beginning of the 3-year period?

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