1. Sec 4-4B Solve Inequalities by addition and SubtractionPg

2. Solve Inequalities
An INEQUALITY is a mathematical sentence that compares quantities.
Symbols
> this symbol means “greater than”.
x > 9 reads, “x is greater than 9”
< this symbol means “less than”.
a < -2 reads, “a is less than -2”

3. Graphing Inequalities
You can graph inequalities on a number line.
When you graph > and <, you use an open circle.
Graph x > 9
Graph a < -2 5 1 2 3 4 6 7 8 9 10 11 12 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10
-11
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4. Graphing Inequalities
Symbols
≥ this symbol means “greater than or equal to”
r ≥ 4 reads, “r is greater than or equal to 4”.
≤ this symbol means “less than or equal to”
b ≤ 2 reads, “b is less than or equal to 2”. 5 1 2 3 4 6 7 8 9 10 11 12 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10
-11
-12

5. Addition and Subtraction Properties of Inequalities
For any real number a, b, and c
Addition Property
If a>b, then a + c > b + c
If a<b, then a + c < b + c
Subtraction Property
If a>b, then a – c > b – c
If a<b, then a – c < b – c

6. Solve Inequalities Solve x + 4 > 7 -4 -4 x > 3 5 1 2 3 4 6 7 8 9
x > 3 5 1 2 3 4 6 7 8 9 10 11 12 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10
-11
-12

7. Solve Inequalities x – 2 ≤ -3 +2 +2 x ≤ -1 5 1 2 3 4 6 7 8 9 10 11 12
x ≤ -1 5 1 2 3 4 6 7 8 9 10 11 12 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10
-11
-12