When an equation is in slope-intercept form:

When an equation is in slope-intercept form:

Examples:Identify the slope of the line and the y-intercept for each

equation. 1. y = 3x +2

2. y = ½ x – 3

  3. y = x –9 4. y = 6 - x

3 2 ½ -3

1 -9 6 -1

Ex.1: What is the equation of the line in slope-intercept form?

m =

b =

4

3

-2

24

3 xy

Using a Graph

Ex. 2: What is the equation of the line in slope-intercept form?

m =

b =

3

5

2

35

2 xy

Graphing linear equations using slope-intercept form (y

= mx + b)

Step 1: Graph the y-intercept.Step 2: Using the slope, find another point.Step 3: Draw a line through the two points.

Ex. 1 Graph the equation:

m =

b = 1

12 xy

2

Ex. 2 Graph the equation:

m =

b =

-4

42

1 xy

2

1

Ex. 3 Graph the equation:

m =

b = 2

23 xy

3

Ex. 4 Graph the equation:

m =

b = 6

6xy

1

Slope Intercept Form: y = 1.0 x + 0.0 x y

-10 -10

-9 -9

-8 -8

-7 -7

-6 -6

-5 -5

-4 -4

-3 -3

-2 -2

-1 -1

0 0

1 1

2 2

3 3

4 4

5 5

6 6

7 7

8 8

9 9

10 10-10

0

10

-10 0 10

Let’s look at a graph of a linear equation in this form.

        What does the slope tell you about a line? How does changing the slope affect your graph?

        What is the y-intercept? What does it tell you about the line? How does changing the y –intercept affect you graph?