11.yes 13. (a)B (b)C (c)D (d)A
In Exercises 21–31, we do not show the graphs.
- (inconsistent system)
- (dependent equations) 29.
- (inconsistent system) 33.It is difficult to read the exact
coordinates of the solution. Thus, the solution cannot be checked. - (a)neither (b)intersecting lines (c)one solution
- (a)dependent (b)one line (c)infinite number of solutions
- (a)neither (b)intersecting lines (c)one solution
- (a)inconsistent (b)parallel lines (c)no solution
- (a)1980–2000 (b)2001; about 750 newspapers
- (a)1997–2002 (b) 2001 (c) 2002 (d) (The y-value
is approximate.) 47. 30 49.B 51.A 53.
Section 4.2 (pages 262–264)
1.The student must find the value of yand write the solution as
an ordered pair. The solution set is. 3.
- 33.To find the total cost, multiply the number of
bicycles by the cost per bicycle , and add the fixed cost.
Thus, gives this total cost (in dollars). 34. - , ; solution set:
36.25; 15,000; 15,000
- 10 10
10–1051 2, 4 26y 1 = 400 x+ 5000 y 2 = 600 x 51 25, 15,000 26y 1 = 400 x+ 5000 y 2 = 600 x1 x 2 1 $400 2 1 $5000 251 4, - 92651 - 2, 1 26 51 x, y 2 |x+ 2 y= 486 51 10, 4 2651 x, y 2 | 2 x-y=- 126 51 2, 6 26 51 2, - 42651 x, y 2 | 3 x-y= 56 EA 41 , - 21 BF 051 7, 3 26 51 - 4, 8 26 51 3, - 226 51 0, 5 2651 3, 0 26 51 3, 9 26y= 29 x- 2 526 E^45 Fy=- 3 x+ 41 1998, 30 2051 x, y 2 |3x+y= 56 51 4, - 32651 1, 3 26 51 0, 2 26 051 4, 2 26 51 0, 4 26 51 4, - 126Section 4.3 (pages 268–270)
1.false; The solution set is. 3. 5.
- solution set: 46. (a)
(b) ; This is a bit more than the actual figure.
47.goals: 894; assists: 1963 49.13 twenties
- solution set: 46. (a)
Summary Exercises on Solving Systems of Linear
Equations (pages 270–271)- (a)Use substitution, since the second equation is solved for y.
(b)Use elimination, since the coefficients of the y-terms are opposites.
(c)Use elimination, since the equations are in standard form with no
coefficients of 1 or. Solving by substitution would involve fractions.
2.System B is easier to solve by substitution because the second equation
is already solved for y. 3. (a) (b) (c)Answers
will vary. 4. (a) (b) (c)Answers will vary.
Section 4.4 (pages 276–281)
1.D 3.B 5.D 7.C 9.the second number; ;
The two numbers are 73 and 25. 11.The Phantom of the Opera:8603;
Cats: 7485 13.Avatar: $429.0 million; Transformers 2: $402.1 million- (a)45 units(b)Do not produce; the product will lead to a loss.
17.quarters: 24; dimes: 15 19.2 DVDs of The Blind Side;
5 Beyoncé CDs 21.$2500 at 4%; $5000 at 5% 23.The Police: $102;
Madonna: $137 25.40% solution: 80 L; 70% solution: 40 L
27.30 lb at $6 per lb; 60 lb at $3 per lb 29.nuts: 40 lb; raisins: 20 lb
31.60 mph; 50 mph 33.35 mph; 65 mph 35.bicycle: 13.5 mph;
car: 49.3 mph 37.boat: 10 mph; current: 2 mph 39.plane: 470 mph;
wind: 30 mph 41.Yady: 17.5 mph; Dane: 12.5 mph
xxyy00
–3–3
2233 xx + 2 + 2yy < 0 << 0
xxyy0044
44
xx + + yy ≤≤ 4 4x-y= 4851 - 4, 2 26 51 5, 3 2651 24, - 1226 51 3, 2 26 51 10, - 122651 - 3, 2 26 EA^2213 , -^2313 BF 51 0, 0 26 51 2, - 326EA^4531 , 314 BF 51 4, - 526 0 51 - 4, 6 2651 - 1, - 1126 51 x, y 2 | 2 x- 3 y= 56 51 9, 4 2651 3, 12 26 51 - 3, 2 26 EA^13 , 21 BF 0 51 3, - 22651 - 5, 2 26 51 - 5, 2 2651 1, 4 26 51 1, 4 26- 1
6.96 1 $6.96 2 1 $0.08 251 0.22375, -442.11 26 y=0.22375x-442.117.18= 2008 a+b 2000 a+b=5.39, 2008 a+b=7.18;EA-^57 , -^27 BF EA^18 , - 65 BF 5.39= 2000 a+bEA13, -^75 BF^51 6, -^42651 x, y^2 |x+^3 y=^66051 x, y 2 |x- 3 y=- 46 0 51 - 3, 2 26 51 11, 15 2651 0, 0 26 51 7, 4 26 51 0, 3 26 51 3, 0 2651 - 2, 3 (^26) EA^12 , 4BF 51 3, - 626 51 0, 4 26
0 51 4, 6 26 51 - 1, - 326
A-10 Answers to Selected Exercises
x
y
0
–2
2
6
6
x
y
0
4
4
–4 x
y
0
2 6
–3
1
- ; The equations to input are and
.- 16 x 45. 10 y 47. 4 x 49.- 2
–10 1010–10Y 2 =^1 - 2X
3
Y 1 =^5 - 4X
5
51 5, - 32639.–10 1010–1051 1, 5 26http://www.ebook777.com
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