Page 290 - Algebra 1

L E S S O N Finding Slope Using the Slope Formula 44
Warm Up
1. Vocabulary The __________ of a line is the steepness of the line. (41)
Name the coordinates of each point.
(20) 2. W
3. X 4. Y
5. Use the table to find the rate of
(41)
change.
4
y
8
Z
Y
x
-8
-4
-4
4
8
W
X
-8
Servings
2
4
8
12
Corn (oz)
8
16
32
48
New Concepts Any two ordered pairs on a line can be used to determine the slope of the line. The slope is a measure of the steepness o_f a line. The slope m of a line
containing points (x , y ) and (x , y ) is m = y2 - y1 . 11 22 x2-x1
Determining Slope from Two Points
Determine the slope of the line that contains the given points.
Math Reasoning
Write Describe the formula for slope using only words.
Example
1
a. (2, 4) and (6, 6)
6 - 2 = _1
b. (−4, 4) and (4, −2)
_
= (-2) -4
4 - (-4) = -_3
SOLUTION
SOLUTION
_ = 6 - 4
m = y2 - y1
slope formula
m = y2 - y1
x-x x-x 21 21
Math Reasoning
Analyze When is the slope an improper fraction?
Substitute x- and y-values.
Simplify.
24
The slope of the line is _1. The slope of the line is -_3. 24
c. (0, −5) and (5, 10) SOLUTION
d. (−6, 5) and (3, −13) SOLUTION
__ m= y2 -y1 slopeformula m= y2 -y1
x-x x-x 21 21
10 - (-5) Substitute x- and = (-13) - 5 __
Online Connection www.SaxonMathResources.com
5 - 0
The slope of the line is 3.
3 - (-6) = -2
The slope of the line is −2. Lesson 44 275
= = 3
y-values. Simplify.