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1 Simplify : [5/3 - 2/x]/[1/5 - 6/x]
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a [25 - 30x]/[x - 60]
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| b [25x - 30]/[1 - 60x] |
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c [25 - 30x]/[x - 90]
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d [25x - 30]/[3x - 90]
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e nota
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2. Simplify : [1
- 4/x + 3/x2]/[1
- 3/x + 2/x2] (Hint:
Factor and cancel.) See example 4, method 1.
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a [x - 2]/[x - 3]
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b [x - 3]/[x - 2]
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c [x - 1]/[x - 2]
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d nota
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3. Simplify : [2 -
1/x - 1/x2]/[1
- 3/x + 2/x2] (Hint: Factor
and cancel.) See example 4 , method 1.
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| a [2x + 1]/[x + 2]
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b [2x + 1]/[x - 2] |
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c [2x - 1]/[x - 2] |
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d nota |
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6.6
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4. Solve: 3/(x - 1) = 5/(x + 1). (Hint:
cross-multiply.) The answer for x is a value in the interval
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| a (5,10) |
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b (0, 5) |
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c (-5, 0) |
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d nota
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| 5. Solve x/2
- 12/x = 1 (Hint: Multiply both sides by the
LCD.) The values for the solution for x are in the intervals
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| a (-7, 0) or
(0,4) |
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b (-2,0) or (0,7) |
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c (-7, 0) or (0,7) |
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d nota |
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e nota
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6. Clean-up costs for pollution
removal in a river are given by f(x) = 250x/(100 - x), in millions of
dollars.
What is the percentage x cleaned if f(x) = 250 (million dollars)?
The value for x is in the interval:
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| a (0,30) |
| b (30,60) |
| c (60,90) |
| d (90,95) |
| e nota
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| 6.7
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7.
Solve for y in the formula: A = xy/(x + y)
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a (Ax - Ay)/x |
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b (Ax +Ay)/x |
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c Ax/(x - A) |
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d Ax/(A + x) |
| e nota |
| 8. A pool can be filled by one pipe
in 2 hours and by a second pipe in 4 hours. How long will it take using
both pipes to fill the pool? See step 4 of example 4. |
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a 3/4 hour |
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b 2 hours |
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c 4/3 hours |
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d nota |
| 6.8 |
9. Hint: See Example 1. Also read
the purple boxes on pages 440 and 441. The cost C of an airplane varies directly
as the number of miles M in the trip. Yo, a 3000 -mile trip costs
$400. What is the cost of a 500-mile trip? Note this direct variation
can also be thought of as a proportion problem:
(3000 miles)/($400) = (500 miles)/x. Thus, you can cross-multiply
and solve for the cost x, i.e. solve: 3000/400 =
500/x. However, it would not hurt to read Example 1. You can use exactly
the same method on this one. Note : This problem is exactly like
application exercise # 11 on page 448.
Answer: $66.70 |
| 7.1 |
10. Simplify these two
problems:
Answers: See Sample Quiz 8, same answers.
4x2 and 2x |
11. Simplify this problem:
Answers See Sample Quiz 8, same
answer.
-4x2 |
| 12. 7.2.
Simplify 81/3 = 2. |
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