Download Lesson 3-1

Lesson 3-1
Inequalities and Their Graphs
How can I use inequalities and their
graphs to compare quantities?
Algebra 5.0 I can solve multi-step problems
including word problems involving linear
inequalities in one variable
Homework
• Textbook page 126-127 #2-36 even
»OR
• Workbook page 227 #4-21 all
Vocabulary
• Inequality –
– A math sentence using one of the inequality
symbols, <, >, <, >, or =
• Solution of an Inequality –
– Any number that makes an inequality true
Identify Solutions by Mental Math
• Ex. 1- Is each number a solution of x < 7?
– A.
– B.
– C.
– D.
– E.
– F.
9
14/2
-5
8
-4.1
0
Identifying Solutions by Evaluating
• Ex. 2 - Is each number a solution of 2 – 5y
> 13?
– A. 3
– B. -4
Graphing Inequalities
•
You can use a graph to indicate all
solutions of an inequality.
1. Draw a number line.
2. Identify the numbers on your number line.
a) a few above and a few below your boundary
number.
3. Determine whether to use an open or closed dot.
a) open indicates boundary number is not part of
the solution
b) closed indicates boundary number is part of the
solution
4. Determine which direction to shade.
Graphing Inequalities continued
• Graph c > -2
• Graph 4 < m
Write an Inequality from a Graph
-5
-4
-3
-2
-1
0
1
2
3
4
-1
0
1
2
3
4
5
6
7
8
-5
-4
-3
-2
-1
0
1
2
3
4
-5
-4
-3
-2
-1
0
1
2
3
4
Application
• Define a variable and write an inequality for
each situation.
Homework
• Textbook pages 126-127 #2-36 even
»OR
• Workbook page 227 #4-21 all