Today’s Objectives
Graph linear equations using intercepts
Graph linear equations using the slope and y-intercept
Find the intercepts of the following equations.
x+y=5
x + 3y = 5
x+0=5
0+y=5
x=5
y=5
x-intercept = 5
y-intercept = 5
x + 3(0) = 5
x+0=5
x=5
0 + 3y = 5
3y = 5
y = 5/3
x-intercept = 5
y-intercept = 5/3
The x-intercept is the point where the line crosses the x axis.
The y-intercept is the point where the line crosses the y axis.
1. Substitute 0 in for y to find the x-intercept.
2. Solve
3. Substitute 0 in for x to find the y-intercept.
4. Solve
Graph using the intercepts of the following equations.
x+y=5
x + 3y = 5
x-intercept = 5
x-intercept = 5
y-intercept = 5
y-intercept = 5/3
Graph each intercept.
Connect the 2 points with a line.
Graph using the intercepts of the following equations.
x+y=5
x + 3y = 5
x-intercept = 5
x-intercept = 5
y-intercept = 5
y-intercept = 5/3
Based upon these graphs…
What are some pros of using the intercepts to graph?
What are some cons of using the intercepts to graph?
Finding Slope Intercept Form
2x + y = 4
y = 4 – 2x
y = -2x + 4
1. y = mx + b
2. b is the y-intercept
3. m is the slope (rise over run)
4. Solve for y
-3x + 4y = -12
4y = 3x - 12
y = ¾x – 12/4
y = ¾x - 3
Graph Using Slope Intercept Form
2x + y = 4
-3x + 4y = -12
y = -2x + 4
1. y = mx + b
2. Graph the intercept
3. From the intercept, count using the slope
(rise) ( up +, down – )
4. Go over to the right
5. Repeat as needed
6. Connect the points with a line.
Graph Using Slope Intercept Form
2x + y = 4
-3x + 4y = -12
y = -2x + 4
y = ¾x - 3
1. y = mx + b
1. y = mx + b
2. Graph the intercept
2. Graph the intercept
3. From the intercept, count using3.
the
From
slope
the intercept, count using the slope
(rise) ( up +, down – )
(rise) ( up +, down – )
4. Go over to the right
4. Go over to the right
5. Repeat as needed
5. Repeat as needed
6. Connect the points with a line. 6. Connect the points with a line.
Graph Using Slope Intercept Form
2x + y = 4
y = -2x + 4
1. y = mx + b
2. Graph the intercept
3. From the intercept, count using the slope
(rise) ( up +, down – )
4. Go over to the right
5. Repeat as needed
6. Connect the points with a line.
-3x + 4y = -12
y = ¾x - 3
Assignment
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