Name
Class
Date
Practice
3-7
Form G
Equations of Lines in the Coordinate Plane
Find the slope of the line passing through the given points.
1.
6
2.
223
y
y
4
4
( 4, 4)
( 1, 2)
1
4
2
2
x
6 4 2 O
2
2
4
4
6
(3, 0)
O
2
2
x
4
2
( 1, 1)
4
4
6
3. (2, 3), (21, 26) 3
4. (26, 22), (23, 26) 243
5. (2, 9), (4, 27) 28
7. y 2 2 5 (x 1 3)
8. y 1 2 5 24(x 1 3)
Graph each line.
6. y 5 3x 2 4
y
y
y
4
4
4
2
2
2
x
4 2 O
2
2
x
x
4 2 O
2
4
2
4 2 O
2
4
4
4
4
4
2
Use the given information to write an equation for each line.
1
10. slope 23 , y-intercept 22 y 5 213x 2 2
9. slope 6, y-intercept 4 y 5 6x 1 4
11.
y
4
(4, 4)
2
(1, 2)
4 2 O
2
2
y 5 23x 1 113
12.
( 2, 5)
y 5 232x 1 2
y
4
2
x
x
4
4 2 O
2
4
(2, 1)
4
4
13. through (22, 0) and (3, 10)
y 5 2(x 1 2)
14. through (10, 2) and (2, 22)
y 2 2 5 12(x 2 10)
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63
Name
3-7
Class
Date
Practice (continued)
Form G
Equations of Lines in the Coordinate Plane
Graph each line.
15. y 5 24
16. x 5 3
17. y 5 5
y
y
x
y
x
x
18. Open-Ended Write equations for three lines that contain the point (0, 2).
Answers may vary. Sample: y 5 2, y 5 x 1 2, y 5 24x 1 2
Write each equation in slope-intercept form.
y 5 212x 2 3
1
21. y 1 1 5 22 (x 1 4)
y 5 22x 1 12
y 5 4x 1 11
19. y 2 3 5 4(x 1 2)
20. y 2 2 5 22(x 2 5)
22. A wireless phone company charges $20 for a basic plan
each month plus $0.25/min for each call.
a. Write an equation to show how much the company
$350
y
charges, where x is the number of minutes used and $250
(400, $120)
y is the total cost. y 5 0.25x 1 20
$150
b. Find the total cost for 300 minutes, 350 minutes,
(0, $20)
$50
and 400 minutes. $95; $107.50; $120
x
(300, $95)
c. Graph the equation using the values for 300 and
50 150 250 350 450
400 minutes.
Minutes
Graph each pair of lines. Then find their point of intersection.
23. y 5 25, x 5 22 (22, 25)
24. y 5 6, x 5 21 (21, 6)
y
y
x
x
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64