Beginning Algebra, 11th Edition

For each pair of equations, give the slopes of the lines and then determine whether the two
lines are parallel, perpendicular,or neither. See Example 6.

SECTION 3.3 The Slope of a Line 209

57. 58. 59.

8 x+ 6 y=- 5

8 x- 9 y= 6

• 8 x+ 6 y= 0


• 4 x+ 3 y= 4
  4 x+ 10 y= 1

2 x+ 5 y= 4

60. 61. 62.

5 x+ 3 y= 2

3 x- 5 y=- 1

2 x+ 3 y= 3

3 x- 2 y= 6

3 x- 5 y=- 8

5 x- 3 y=- 2

63. 64.

4 x+ 3 y= 12

3 x- 4 y= 12

x- 5 y=- 10

5 x- y= 1

EXERCISES 65–70

FOR INDIVIDUAL OR GROUP WORK

FIGURE Agives public school enrollment (in thousands) in grades 9–12 in the United

States. FIGURE Bgives the (average) number of public school students per computer.

FIGURE A FIGURE B

Work Exercises 65–70 in order.

65.Use the ordered pairs 1990, 11,338 and 2005, 14,818 to find the slope of the

line in FIGURE A.

66.The slope of the line in FIGURE Ais. This means that

( positive/negative)

during the period represented, enrollment.

(increased/decreased)

67.The slope of a line represents the rate of change of the line.On the basis of FIGURE A,

what was the increase in students per yearduring the period shown?

68.Use the given information to find the slope, to the nearest hundredth, of the line in

FIGURE B.

69.The slope of the line in FIGURE Bis. This means that

( positive/negative)

the number of students per computer during the period

represented. (increased/decreased)

70.On the basis of FIGURE B, what was the decrease in students per computer per year

during the period shown?

1 2 1 2

RELATING CONCEPTS

YELLOWBIRD BUS COMPANY

Source: U.S. Department of Education.

Year

15,000

14,000

13,000

12,000

11,000

0

1990 1995 2005

Number of Students

(in thousands)

2000

11,338

14,818

Public School Enrollment Grades 9–12

y

x 0

5

10

15

20

25

'90 '93 '96 '99 '02 '05'07

Source: Quality Education Data, Inc.

Number of Students

per Computer

20

3.8

Year

Students Per Computer

y

x