1. Lesson 3.4 Graphing Horizontal and Vertical Lines
Objective- To graph horizontal and vertical lines.
Graph x + y = 5 x y -2 7 y -1 6 5
Line is oblique 1 4 2 3 3 2 4 1 x 5 6 -1
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series
Algebra 1 by James Wenk © 2003 published by TEACHINGpoint

2. Graph. y = 3 Line is Horizontal x y y -2 3 -1 3 3 1 3 2 3 x 3 3 4 33 1 3 2 3 x 3 3 4 3
Any line in the
form y = k will
be horizontal. 5 3
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

3. Graph. x = -2 Line is Vertical x y y -2 -2 -2 -1 -2 -2 1 -2 2 x -2 3-2 1 -2 2 x -2 3 -2 4
Any line in the
form x = k will
be vertical. -2 5
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

4. Types of Lines Ax + By = C y = k x = k 3x - 2y = 5 y = -7 Oblique
Horizontal
Vertical
Equation
form
Ax + By = C
y = k
x = k
Example
3x - 2y = 5
y = -7
Universal
constants
A = 3
k = -7
B = -2
C = 5
A, B and C are integers (no fractions or decimals).
k represents a rational number.
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

5. Review x = k y = k Horizontal Line Vertical Line Perpendicular
to y-axis.
Perpendicular
to x-axis.
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

6. A) Graph x = -4 on a number line.
B) Graph x = -4 on a coordinate plane. y x
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

7. = where the line crosses the x-axis y-intercept
Finding Intercepts
x-intercept
= where the line crosses the x-axis
y-intercept
= where the line crosses the y-axis
Horizontal
Vertical
y = 2
x-int.= none
x = -1
x-int.= -1
y-int.= 2
y-int.= none y y x x
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

8. = where the line crosses the x-axis y-intercept
Finding Intercepts
x-intercept
= where the line crosses the x-axis
y-intercept
= where the line crosses the y-axis
Oblique
x-intercept
y-intercept
y = 2x + 3
(set y = 0)
(set x = 0)
y = 2x + 3
y = 2x + 3 x y y -3 -2 -1 1 2
0 = 2x + 3
y = 2(0) + 3 -3 -1
y = 3
-3 = 2x 1 x 3 5 7
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

9. Find the x-intercept and y-intercept.
x = 5 or (5,0)
none 2)
none
3) x = -1
(-1,0)
none
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

10. Find the x-intercept and y-intercept.
4) 4x + 2y = 6
(Set y = 0)
(Set x = 0)
4x + 2y = 6
4x + 2y = 6
4x + 2(0) = 6
4(0) + 2y = 6
4x = 6
2y = 6
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

11. Find the x-intercept and y-intercept.
5) 3x - y = -5
(Set y = 0)
(Set x = 0)
3x - y = -5
3x - y = -5
3x - (0) = -5
3(0) - y = -5
3x = -5
-y = -5
-1(-y = -5)
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series