Graphing Lines Using Slope Intercept Form

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Graphing Lines Using Slope Intercept Form
Unit 3 Exploring Linear Relationships
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Earlier in this unit, you graphed an equation
using a table of values and plotted points to
make a line.
Today you will learn another method to graph an
equation. This method is called the
slope-intercept form.
The linear equation ymxb is written in
slope-intercept form where m is the slope and b
is the y-intercept.
y-intercept
slope
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Recall that the slope of a line can be calculated
using y2 y1 x2 x1 Slope can also be
counted using a graph by doing rise run
The y-intercept of a line is where the line
intersects the y-axis
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ZERO Rise ALL run!
Slope 0 y-int 2 Equation y (0)x 2 y
2
 
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Now lets work BACKWARDS!! ? Instead of finding
information from a graph lets use information
to make a graph!!
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Graph the equation y 6x 3.
y
1. Plot the y-intercept.











2. Use slope to locate second point.
x
3. Draw a line through the two points.

How do you check if you have the correct graph?
Using the coordinate of each point, substitute
into the original equation. Does it produce true
statements?
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Graph the equation y 6x 3.
y
coordinate for y-intercept
y 6x 3
( , )
0
3











3 6(0) 3
3 0 3
x
Absolutely!
3 3

coordinate for other points
y 6x 3
( , )
1
-3
-3 6(1) 3
-3 -6 3
-3 -3
Using the coordinate of each point, substitute
into the original equation. Does it produce true
statements?
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Example 1 Graph the equation y 3x 2.
Example 2 Graph the equation y 4x 5.
Example 3 Graph the equation
Example 4 Graph the equation
How do you know by looking at these equations,
that they will NOT result in graphs of horizontal
or vertical lines?
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Ex 1 y 3x 2.
Ex 2 y 4x 5.





















x
x



Ex 3
Ex 4






















x
x


y
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Write the equation in slope-intercept form. Then
graph.
The equation
Rewrite in slope-intercept form (i.e., solve for
y).
1
y
Graph












y-intercept is 3

slope is 2
x
How do you check if you have the correct graph?
Using the coordinate of each point, substitute
into the original equation. Do they produce true
statements?
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Write the equation in slope-intercept form. Then
graph.
Example 5
Example 6
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Example 6
Example 5
y-int. is 3
y-intercept is 2
slope is 5
Remember the negative can go in the numerator or
denominator.























x
x

How do you check if you have the correct graph?

Using the coordinate of each point, substitute
into the original equation. Does it produce true
statements?
y
y
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