Lesson 7-5 Pages 350-354

Solving Inequalities by Multiplying or

Dividing

What you will learn!1. How to solve inequalities by multiplying or dividing by a positive number.

2. How to solve inequalities by multiplying or dividing by a negative number.

What you really need to know!

Use the Multiplication and Division Properties of Inequalities. When you multiply or divide each side of an inequality by a positive number, the inequality remains true.

What you really need to know!Know this secret!

For an inequality to remain true when multiplying or dividing each side by a negative number, you must reverse the direction of the inequality symbol!

Example 1: Solve:

549 x9 9

6x

Example 1b: Solve:

49

d

36d

)9( )9(

Example 2:

Martha earns $9 per hour working for a fast food restaurant. Which inequality can be used to find how many hours she must work in a week to earn at least $243?

AA 9x < 2439x < 243BB 9x 9x ≥ 243≥ 243CC 9x > 2439x > 243DD 9x 9x ≤ 243≤ 243

AA 9x < 2439x < 243BB 9x 9x ≥ 243≥ 243CC 9x > 2439x > 243DD 9x 9x ≤ 243≤ 243

Example 3:

Solve the inequality and graph.

75

x)5( )5(

35x

35x

-35 -34-37 -36-39 -38 -32-33

Example 3b:

Solve the inequality and graph.

279 x

3x

9 9

5 63 41 2 87

3x

Page 353

Guided Practice

#’s 4-13

Pages 350-352 with someone at home and

study examples!

Read:

Homework: Pages 353-354

#’s 14-38 even

#’s 42-57 all

Practice Quiz 2 #’s 1-10PA Lesson Check 7-5

Link to Lesson 7-5 Review Problems

Page

741

Lesson 7-5

PA Lesson Check 7-5