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M. Pickens 2006 
Slope
M. Pickens 2006 
Objectives 
• To learn what slope is 
• To learn what a line looks like when it 
has positive, negative, zero or undefined 
slope 
• To learn how to find the slope of a graph 
• To learn how to find the slope given 2 
points 
• To learn how to find the slope of a table
= D (change in y) 
M. Pickens 2006 
What is Slope? 
Slope is the rate of change of a line 
slope = rise x 
run 
slope y 
D 
(change in x) 
slope = y - 
y 
2 1 
x - 
x 
2 1
What does the line look like when… 
• You have positive slope? 
• You have negative slope? 
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• You have zero slope? 
• You have NO slope?
M. Pickens 2006 
Slope 
Mountain 
Ski Resort 
Positive 
slope, 
+ work 
Negative 
slope, 
- work 
Zero 
slope is 
zero fun! 
NO 
slope. 
Oh No!!!! 
T. Merrill 2005
M. Pickens 2006 
Lets Cheer 
Positive, 
Negative 
Zero 
NO 
X-Axis 
Y-Axis 
Go, Go, Go
What Type of Slope is 
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Shown? 
Positive Slope 
Negative Slope 
Zero Slope 
No 
Slope/Undefined
M. Pickens 2006 
Slope of a Graph 
• When slope is positive or negative we 
need to find the actual value of the 
slope or rate of change 
• On a graph we find slope using the 
formula 
slope = rise 
run 
How far up or down it changes 
How far left or right it changes
= 2 
M. Pickens 2006 
Slope of a Graph 
1.First pick two points 
on the line 
The points need to be 
where the lines cross 
so they are integers 
2. Then find the rise and 
run 
3. Determine if the slope 
of the line is positive 
or negative 
Rise = 2 
Run = 3 
slope = rise 
run 
3
= 10 = 5 
M. Pickens 2006 
Slope of a Graph 
1.First pick two points 
on the line 
The points need to be 
where the lines cross 
so they are integers 
2. Then find the rise and 
run 
3. Determine if the slope 
of the line is positive 
or negative 
Rise = 10 
Run = 2 
slope = rise 
run 
2
Slope of a Graphed Line 
RISE 
1 
- 4 = - 
0 = 
4 
- 8 = - 
3 
2 
M. Pickens 2006 
Find the slope of each line below 
Find the slope of each 
line below 
x 
y 
Slopes: = 
RUN 
1 
4 
4 
4 
0 
6 
1 
2 
4 
= undefined 
0
Slope of line through 2 points 
• To find the slope of a line through 2 
given points we use the formula 
slope = y - 
y 
2 1 
x - 
x 
• For example, Find the slope of a line 
that goes through (--3, 3 5) 5 and (2, 2 18) 
18 
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2 1 
X1 y1 X2 y2 
slope = y - 
y 
2 1 
x - 
x 
2 1 
= 13 
5
Given two points on a line, find the slope: 
1. (9, 2), (8, -7) 
= - = 
9 
- 
- 3 
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2. (-4, 4), (-7, 2) 
- 
7 4 
2 4 
2 4 
3. (5, -1), (9, -4) 
y y 
2 1 
x 2 x 
1 
rise 
run 
- 
- - 
8 9 
7 2 
- 
1 
- 
y - 
y 
- 
2 1 
x 2 x 
1 
= 
- - - 
= 2 
= 
= 
2 
- - - 
9 5 
4 1 
- 
= - 
- 
- 
- + 
3 
7 4 
= 
- + 
9 5 
4 1 
- 
4 
X1 y1 X2 y2 
= 9 
X1 y1 X2 y2 
X1 y1 X2 y2 
3
Given two points on a line, find the slope: 
4. (5, 2), (1, 0) 
= - = 
2 
- 
1 3 Undefined, NO slope 
= 1 
2 2 0 = 
0 
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5. (3, -3), (3, -1) 
- - - 
3 3 
1 3 
- + 
6. (-4, -2), (4, -2) 
y y 
2 1 
x 2 x 
1 
rise 
run 
- 
- 
1 5 
0 2 
- 
4 
- 
y - 
y 
- 
2 1 
x 2 x 
1 
= 
- 
= 
2 
= = 
- - - 
4 4 
2 2 
- - 
- 
0 
3 3 
= 
- + 
4 + 
4 
8 
X1 y1 X2 y2 
2 
X1 y1 X2 y2 
X1 y1 X2 y2
= + 
4 2 
- 
= 6 = 3 
M. Pickens 2006 
Slope of a Table 
• In a table we can use the same formula. Pick 
any two pairs in the table for coordinates 
x y 
-4 -17 
1 -2 
3 4 
8 19 
10 25 
slope = y - 
y 
2 1 
x - 
x 
2 1 
Pick any two rows. 
If it is linear it will be the same 
no matter which two rows you pick 
x1 
x2 
y1 
slope = - - 
y2 3 1 
4 2 
- 
3 1 
2
slope = y - 
y 
2 1 
x - 
x 
= - 
3 2 
- - - 
= - 
3 2 
- + 
= 1 
M. Pickens 2006 
Slope of a Table 
• Find the slope for each table below 
x y 
-3 4.25 
-1 2.75 
0 2 
1 1.25 
5 -1.75 
x y 
-8 2 
-6 3 
-3 4.5 
-1 5.5 
0 6 
slope = y - 
y 
2 1 
x - 
x 
2 1 
= - 
2.75 4.25 
- - - 
1 3 
= -1.5 
2 
= -0.75 
= - 3 
4 
2 1 
6 8 
6 8 
2
slope = y - 
y 
2 1 
x - 
x 
= - - - 
8 8 
- - - 
= - + 
8 8 
- + 
= 0 = 0 
M. Pickens 2006 
Slope of a Table 
• Find the slope for each table below 
x y 
slope = y - 
y 
2 1 
x y 
-10 17 
x - 
x 
2 1 
-3 -8 
-5 10 
= 10 - 
17 
-1 -8 
-1 4.4 
- 5 - - 
10 
0 -8 
5 -4 
= - 
1 -8 
10 -11 
4 -8 
10 17 
- + 
5 10 
= - 7 
5 
2 1 
1 3 
1 3 
2
slope = y - 
y 
2 1 
x - 
x 
2 1 
M. Pickens 2006 
Conclusion 
• Slope is: 
the rate of change of a line 
slope = rise 
run 
• Describe the slope of each of the following 
Negative slope Undefined/ 
No slope 
Positive slope Zero/0 slope