# Graphing Linear Equations continued

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```					Graphing Linear Equations
continued
Integrated Math 2 - Lesson 1B
Mr. Lopez
Do Now - Review

•   What is the slope and y-intercept for the
following equations?

2x – y = 5
4y – 8 = 2x

•   Graph the equation 2x = y – 1

2x – y = 5         4y – 8 = 2x
-2x      -2x           +8       +8
-y = -2x + 5       4y = 2x + 8
-1    -1   -1      4        4    4

y = 2x – 5         y = ½x + 2
m = 2 or m = 2/1   m=½
b = -5             b=2
Do Now - Review

• Graph the equation 2x = y – 1
 Move the equation around so that it in y = mx + b
form
2x = y – 1
+1    +1                        2x = y – 1
2
2x + 1 = y
2
Or                  -2
Y = 2x + 1                    -2
Finding the Intercepts of a Line

• The intercepts of a line are the points where it
crosses the “x” and “y” axis.

• As of know, we can get the y-intercept from the
formula y = mx + b because the “b” represents
the y-intercept (0, b)

• There is another way to find the y-intercept
without using the formula but sometime it
doesn’t always work out so nicely.
Finding the Intercepts of a Line

• To find the y-intercept, simply to the equation
as it is and substitute the “x” with a 0 and
solve for “y”. We can do this because
remember from before, the y-intercept is the
point where it crosses the y-axis and it’s
coordinate has a 0 for “x”.
Example: 2x – 3y = 18
2(0) – 3y = 18
-3y = 18
y = -6
So the y-intercept (0, -6)
Finding the Intercepts of a Line

• The same can be done for finding the
x-intercept. The x-intercept is the point where
the line crosses on the x-axis.
• To find the x-intercept, substitute 0 where “y” is
and solve for “x”.
Example: 2x – 3y = 18
2x – 3(0) = 18
2x = 18
x=9
So the x-intercept (9, 0)
Practice

• Find the “x” and “y” intercepts for the following 2
equations
3x – y = 6                 2x = y – 4
Graphing Lines Using Intercepts

•     Graphing a line by using the “x” and “y”
intercepts takes 4 steps
1. Start by finding the    1. 3x + y = 6
y-intercept
Set x = 0 and solve for y.
Graphing Lines Using Intercepts

2. Find the x-intercept.   2. 3x + y = 6
Set y = 0 and solve for x
Graphing Lines Using Intercepts

3. On the graph, plot
the two intercepts
and connect them
with a straightedge.