Name_________________________________________________________
Date __________
Graphing Linear Equations in Slope-Intercept Form
2.3
For use with Activity 2.3
Essential Question How can you describe the graph of the equation
y = mx + b?
1
ACTIVITY: Finding Slopes and y-Intercepts
Work with a partner.
•
Graph the equation.
•
Find the slope of the line.
•
Find the point where the line crosses the y-axis.
1
2
b. y = − x + 2
a. y = − x + 1
y
−3
−2
y
3
3
2
2
1
1
−1
1
2
3
x
−3
−2
−1
−1
−1
−2
−2
−3
−3
c. y = − x − 2
d. y =
−2
3
2
2
1
1
1
2
3
x
−3
−2
−1
−1
−1
−2
−2
−3
−3
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3
x
1
2
3
x
y
3
−1
2
1
x +1
2
y
−3
1
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Name _________________________________________________________ Date _________
2.3
Graphing Linear Equations in Slope-Intercept Form (continued)
Inductive Reasoning
Work with a partner. Graph each equation. Then complete the table.
Equation
1
2
1a
2. y = − x + 1
1b
3. y = − x + 2
1c
4. y = − x − 2
1d
5. y =
Description of Graph
Line
Slope of
Graph
−
1
2
Point of Intersection
with y-axis
(0, 1)
1
x +1
2
6. y = x + 2
7. y = x − 2
8. y =
1
x −1
2
1
2
9. y = − x − 1
10. y = 3 x + 2
11. y = 3 x − 2
12. y = − 2 x + 3
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Name_________________________________________________________
2.3
Date __________
Graphing Linear Equations in Slope-Intercept Form (continued)
What Is Your Answer?
13. IN YOUR OWN WORDS How can you describe the graph of the equation
y = mx + b?
a. How does the value of m affect the graph of the equation?
b. How does the value of b affect the graph of the equation?
c. Check your answers to parts (a) and (b) with three equations that are
not in the table.
14. Why is y = mx + b called the “slope-intercept” form of the equation
of a line?
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Name _________________________________________________________ Date _________
2.3
Practice
For use after Lesson 2.3
Find the slope and y-intercept of the graph of the linear equation.
2. y = 4 −
1. y = − 3 x + 9
2
x
5
3. 6 + y = 8 x
Graph the linear equation. Identify the x-intercept.
4. y =
2
x +6
3
5. y − 10 = − 5 x
y
O
y
x
x
O
6. The equation y = − 90 x + 1440 represents the time (in minutes) left after
x games of a tournament.
a. Graph the equation.
y
x
b. Interpret the x-intercept and slope.
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