Inequalities

Intro to Algebra

Inequality

Not equal….what else could it be?

•Less Than•Greater Than

Reading an Inequality Statement

• We read math statements just like anything else (Left to Right)

• There are two signs; < and >• If you read the point (small part) first it means

less than (<)• If you read the open part (big part) first it

means greater than (>)

Read these statements

1. x > 7

2. -8 > y

3. z < -2

2 other inequalitites

≥ and ≤• The line underneath means it could be equal

to also

• ≥ means greater than or equal to

• ≤ means less than or equal to

Graphing Inequalities

• To graph, it is best to have your variable on the left

• How do we switch it if it is on the right?

19 > x

• You can switch the statement by just swapping the terms, but then you have to flip the inequality sign too.

x < 19

Rewrite the statements to have the variable on the left.

1. -2 < x

2. 18 ≥ y

3. 0 ≤ a

Graphing an Inequality

• Once the variable is on the left we can start graphing.

• We will make a point on the number that is on the right.

• Our point will be open if the sign is < or >• Our point will be filled in if the sign is ≤ or ≥

Graphing Inequalities

• After our point is made, we will have to mark what direction we go from the point.

• Go in the direction the arrow points!• Go right if the sign is > or ≥• Go left if the sign is < or ≤

Graph the Inequality

x > 2

Graph the Inequality

x ≥ -4

Graph the Inequality

0 ≤ a

Graph the Inequality

7 > b

Graph the Inequality

c ≥ 3

Graph the Inequality

10 < y

Graph the Inequality

x ≤ -3

Graph the Inequality

x ≥ -8

We will also need to write an inequality for a give graph

• Write the variable on the left, and the number the dot is on on the right.

• Your arrow should go in the direction the shaded part is going.

• If the dot is filled in we put a line underneath the inequality sign.

Write an Inequality for the graph