The Algebra Teacher\'s Guide to Reteaching Essential Concepts and Skills

Name Date

WORKSHEET 4.6: FINDING THE SLOPE OF A LINE, GIVEN TWO

POINTS ON THE LINE

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The slope(m)of a line through two points can be found by using the formula

m=

y 2 −y 1

x 2 −x 1

.(x 1 ,y 1 )and(x 2 ,y 2 )are two points on the line.x 2 =x 1 Follow the steps below

to find the slope of a line when given two points on the line:

1. Identify one point as(x 1 ,y 1 )and the other as(x 2 ,y 2 ).


2. Substitute the values in the formula and solve form.


3. Simplify the fractions and change improper fractions to whole numbers, if possible. (Do
   not change improper fractions to mixed numbers.)

EXAMPLE

Use the formula to find the slope of the line through (−3,−1) and (−2, 8).

x 1 =−3,y 1 =−1,x 2 =−2,y 2 =8orx 1 =−2,y 1 =8,x 2 =−3,y 2 =− 1

m=

y 2 −y 1

x 2 −x 1

m=

y 2 −y 1

x 2 −x 1

m=

8 −(−1)

− 2 −(−3)

=

9

1

= 9 m=

− 1 − 8

− 3 −(−2)

=

− 9

− 1

= 9

DIRECTIONS: Find the slope of the line through the given points.

1. (−1, 9), (0, 5) 2.(0, 0), (2,−4) 3.(9, 5), (−7, 1)

4.(3,−4), (9, 4) 5.(2, 6), (4, 6)

CHALLENGE:Dominic said that the slope of the line between (−1, 0) and (2, 4)

is

3

4

. Do you agree? If you disagree, find his error and the correct slope.

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Copyright

©

2011 by Judith A. Muschla, Gary Robert Muschla, and Erin Muschla. All rights reserved.