74 CHAPTER 1 The Real Number System
59. 60.
61. 62.
63. 64.
65. 66.
67. 68.
69. 70.
71. 72.
73. 74.
75. 76.
77. 78.
79. 80.
Translate each phrase into a mathematical expression. Use x as the variable. Combine like
terms when possible. See Example 4.
81.Five times a number, added to the sum of the number and three
82.Six times a number, added to the sum of the number and six
83.A number multiplied by 7, subtracted from the sum of 13 and six times the number
84.A number multiplied by 5, subtracted from the sum of 14 and eight times the number
85.Six times a number added to 4, subtracted from twice the sum of three times the num-
ber and 4 (Hint: Twicemeans two times.)
86.Nine times a number added to 6, subtracted from triple the sum of 12 and 8 times the
number (Hint: Triplemeans three times.)-
-
- 7.5 12 y+ 42 - 2.9 13 y- 62 8.4 16 t- 62 +2.4 19 - 3 t 2
- 41 - 3 x+ 32 - 16 x- 42 - 2 x+ 1 - 518 x+ 22 - 15 x- 32 - 3 x+ 17
- 21 - 3 k+ 22 - 15 k- 62 - 3 k- 5 - 213 r- 42 - 16 - r 2 + 2 r- 5
812 k- 12 - 14 k- 32 613 p- 22 - 15 p+ 12- 312 r- 32 + 215 r+ 32 - 415 y- 72 + 312 y- 52
- 515 y- 92 + 313 y+ 62 - 312 t+ 42 + 812 t- 42
-
7
5
1 t- 152 -1
2
- t
4
3
1 y- 122 -1
6
y- 6 - 41 y- 72 - 4 - 51 t- 132
1003 0.05 1 x+ 324 1003 0.06 1 x+ 524214 x+ 62 + 3 416 y- 92 + 72 p^2 + 3 p^2 - 8 p^3 - 6 p^35 y^3 + 6 y^3 - 3 y^2 - 4 y^2EXERCISES 87–90FOR INDIVIDUAL OR GROUP WORK
A manufacturer has fixed costs of $1000to produce widgets. Each widget costs $5to
make. The fixed cost to produce gadgets is $750, and each gadget costs $3to make.
Work Exercises 87–90 in order.
87.Write an expression for the cost to make xwidgets. (Hint:The cost will be the sum
of the fixed cost and the cost per item times the number of items.)
88.Write an expression for the cost to make ygadgets.
89.Use your answers from Exercises 87 and 88to write an expression for the total cost
to make xwidgets and ygadgets.
90.Simplify the expression you wrote in Exercise 89.RELATING CONCEPTS
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