Interval Notation Notes

Interval Notation

Communicating sets of numbers

​Instead of using inequalities we can use another type of notation called interval notation.

What is interval notation?

This video will further explain interval notation.

Multiple Choice

Look at the Graph. Write the inequality in interval notation.

• [-4, -1)

• (-4, -1)

• (-4, -1]

• [-4, -1]

Multiple Choice

Express the following in Interval Notation

-9 < x ≤ -4

• [-9, -4]

• (-9,-4]

• [-9, -4]

• (-9,-4)

​Remember that parenthesis are for < and >. And brackets are for

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Example. Rewrite using interval notation.

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​Answer.

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​Remember that parenthesis are for < and >. And brackets are for

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Example 2. Rewrite using interval notation.

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Multiple Choice

Look at the picture. Which number line corresponds to [-2, 5]?

• Graph 1

• Graph 2

• Graph 3

• Graph 4

Multiple Choice

Express the following in Interval Notation

-8 ≤ x < 8

• [-8, 8]

• [-8,8)

• (-8, 8]

• (-8, 8)

Multiple Choice

Write the inequality in interval notation. x > -1

• (-∞, -1)

• (-1, ∞]

• (-∞, -1]

• (-1, ∞)

​Remember that parenthesis are for < and >. And brackets are for

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Example 2. Rewrite using interval notation.

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​Answer.

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(1,5]

Multiple Choice

What interval notation does the number line graph represent?

• [∞, -5)

• (∞, -5)

• [-5, ∞)

• (-5, ∞)

Multiple Choice

Write the following in interval notation

x ≥ 100

• (0, 100] (Real quick)

• (∞, 100]

• [100, ∞)

• (∞, 100)

Multiple Choice

Write the following solution in interval notation:

z < 20

• ( -∞ , 20 )

• ( 20,∞)

• ( -∞ , 20)

• ( -∞ , 20]

Multiple Choice

Write the following in interval notation

x < 8

• (8, ∞)

• (8, -∞)

• (-∞, 8)

• [-∞, 8]

Multiple Choice

When graphing b< 6 would you use an open or closed circle?

• open
• closed

Multiple Choice

Look at the picture. Select the correct interval notation for the given number line.

• (-∞, -8) U (-4, ∞)

• (-∞, -8] U [-4, ∞)

• (-8, -4)

• [-8, -4]

Multiple Choice

Look at the picture. Which graph best represents the solution set (-∞, -2) U (5, ∞)?

• Graph 1

• Graph 2

• Graph 3

• Graph 4

Multiple Choice

Write the following in interval notation

x > 6 and x ≤ 10

• (-∞, 6) and (10, ∞)

• [6, 10)

• (-∞, 6] and [10, ∞)

• (6, 10]

Multiple Choice

Look at the graph. Write the inequality in interval notation.

• (-2,5)

• (-∞,-2)⋃(5,∞)

• [-2,5]

• (-∞,-2]∪[5,∞)