Intermediate Algebra (11th edition)

Solve each system by elimination. If the system is inconsistent or has dependent equations,
say so. See Examples 6 – 9.

SECTION 4.1 Systems of Linear Equations in Two Variables 221

41.

2 x- 5 y= 24

• 2 x+ 3 y=- 16 42.
  
  
  • 6 x- 11 y= 1
  
  
  
  

6 x+ 5 y=- 7 43.

3 x+ y= 8

2 x- 5 y= 11

44.

• 4 x+ y=- 3


• 2 x+ 3 y= 1 45.
  5 x+ 3 y= 1

3 x+ 4 y=- 6 46.

3 x+ 2 y= 2

4 x+ 3 y= 1

47.

• 14 x- 4 y=- 12

7 x+ 2 y= 6 48.

4 x- 16 y= 8

x- 4 y= 2 49.

4 x+ 2 y= 3

3 x+ 3 y= 0

50.

4 x- 2 y= 2

8 x+ 4 y= 0 51.

x- y= 12

5 x- 5 y= 3 52.

• 4 x+ 6 y= 14

2 x- 3 y= 7

53.

2 x- 2 y= 0

x+ y= 0 54.

• 2 x- y= 0

3 x+ 3 y= 0 55.

• x+

2

5

y=-

8

5

x-

1

2

y= 2

56.

2

3

x+

1

3

y= 1

3

2

x+ y= 3 57.

1

2

x+ 2 y=

4

3

1

2

x+

1

3

y=

49

18

58.

1

10

x+

1

3

y=

5

6

1

5

x+

1

7

y=

12

5

Write each equation in slope-intercept form and then tell how many solutions the system has.
Do not actually solve. See Example 10.

59. 6 x+ 14 y= 3

3 x+ 7 y= 4 60.

4 x- 8 y= 1

• x+ 2 y= 8

61.

6 x=- 9 y+ 3

2 x=- 3 y+ 1 62.

10 x=- 4 y+ 2

5 x=- 2 y+ 1

Solve each system by the method of your choice. See Examples 3 – 9.( For Exercises 63 – 65,
see your answers to Exercise 40.)

63. x-y=- 5

3 x+y=- 7 64.

y= 11 x

6 x-y= 5 65.

9 x+ 8 y= 7

3 x- 2 y= 0

66.

2 x+ 3 y= 30

3 x- 5 y= 7 67.

• 3 x+ y= 18

2 x+ 3 y= 10

68.

1

4

x+

1

2

y= 12

1

6

x+

1

3

y= 8 69.

4 x- y=- 2

1

2

x-

1

8

y=-

1

4

70.

0.4x+ y= 9

0.2x+0.5y= 6 71.

0.5x+0.4y=0.7

0.3x+0.2y=0.4

72.Explain why the system would be more difficult to solve by substitution
8 x- 5 y= 4

3 x+ 7 y= 19

than.

3 x- 2 y= 4

x+ 7 y= 8