1. 3.5 Lines in the Coordinate Plane
Chapter 3: Parallel and Perpendicular Lines

2. 3.5 Lines in the Coordinate Plane
Slope-Intercept Form: y = mx + b
m: slope
b: y-intercept
(x, y): point

3. Slope-Intercept Form Identify the slope and y-intercept for each:
a. y = 3x b. y = -2x + 5
c. y = ½x – 5 d. y = 3x – ½
e. y = -5x – 4 f. y = 0.2x + 0.7

4. Graphing Lines in Slope-Intercept Form
Graph the line y = 3/4x + 2
m = b =
Graph the line y = x + 2
m = b =
Graph the line y = 3x + 4

5. Graphing Lines in Slope-Intercept Form
Graph the line y = -½x – 2
m = b =
Graph the line y = ½x – 1
Graph the line y = -5/3 x + 2
m = b =

6. Standard Form Ax + By = C (3x + 2y = 5)
To Graph from Standard Form, find the x- and y- intercepts:
To find the x-intercept, plug in 0 for y.
To find the y-intercept, plug in 0 for x.

7. Graphing Using Intercepts
Graph 6x + 3y = 12
Find the x-intercept:
Find the y-intercept:

8. Graphing Using Intercepts
Graph -2x + 4y = -8
Find the x-intercept:
Find the y-intercept:

9. Transforming to Slope-Intercept Form
Graph 4x – 2y = 9, using slope-intercept form:

10. Transforming to Slope-Intercept Form
Graph -5x + y = -3, using slope-intercept form:

11. Write each equation in slope-intercept form and graph the line:
y = 2x + 1
y – 1 = x
y + 2x =4
8x + 4y = 16
2x + 6y = 6
¾x – ½y = 1/8

12. Point-Slope Form y – y1 = m(x – x1)
(1, 3) and slope 2: (y – 3) = 2(x – 1)

13. Using Point-Slope Form
Write an equation of the line through point
P(-1, 4) with slope 3.
y – y1 = m(x – x1)
y – y1 = m(x – x1)

14. Using Point-Slope Form
Write an equation of the line through point
P(2, -4) with slope -1.

15. Write an equation of the line in point-slope form:
P(2, 3), slope = 2
I(4, -1), slope = 3
R(-2, -6), slope = -4
A(6, 1), slope = ½
T(-3, 5), slope -1
E(0, 4), slope 1

16. Writing an Equation of a Line Given Two Points:
Write an equation of the line through A(-2,3) and B(1,-1):
Find the slope:
Use one point and write the equation in point-slope form:

17. Writing an Equation of a Line Given Two Points:
Write an equation of the line through P(5,0) and
Q(7,-3)
Find the slope:
Use one point and write the equation in point-slope form:

18. Write an equation in point-slope form of the line that contains the given points:
D(0,5) E(5,8)
F(6,2) G(2,4)
H(2,6) I(-1,3)
J(-4,4) K(2,10)
L(-1,0) M(-3,-1)
N(8,10) O(-4,2)

19. Equations of Horizontal and Vertical Lines:
A Horizontal Line cuts through the y-axis, so the equation is y =
A Vertical Line cuts through the x-axis, so the equation is x =
y = 4
x = 3

20. Equations of Horizontal and Vertical Lines:
Write the Equations of the Horizontal and Vertical line that goes through the point:
(3, 2) Horizontal:
Vertical:
(4, 7) Horizontal:
(2, 6) Horizontal:

21. Homework pg 155 1-37all Workbook 3.5 All
Show all work on a separate sheet of paper