### About Interval Notation:

When solving linear inequalities in one variable, the solution is often a range of numbers or an interval. To display an interval, we have a special type of notation, known as interval notation. We can also use set-builder notation or graph the interval using a number line.

Test Objectives
• Demonstrate the ability to write an interval using interval notation
• Demonstrate the ability to write an interval using set-builder notation
• Demonstrate the ability to graph an interval on a number line
Interval Notation Practice Test:

#1:

Instructions: Write each in interval notation, set-builder notation, and graph the interval.

a) x ≥ 9

#2:

Instructions: Write each in interval notation, set-builder notation, and graph the interval.

a) x < -7

#3:

Instructions: Write each in interval notation, set-builder notation, and graph the interval.

a) x > 2

#4:

Instructions: Write each in interval notation, set-builder notation, and graph the interval.

a) -9 ≤ x ≤ 9

#5:

Instructions: Write each in interval notation, set-builder notation, and graph the interval.

a) -4 < x ≤ 2

Written Solutions:

#1:

Solutions:

a) [9, ∞) - interval notation

{x | x ≥ 9} - set-builder notation #2:

Solutions:

a) (-∞, -7) - interval notation

{x | x < -7} - set-builder notation #3:

Solutions:

a) (2, ∞) - interval notation

{x | x > 2} - set-builder notation #4:

Solutions:

a) [-9, 9] - interval notation

{x | -9 ≤ x ≤ 9} - set-builder notation #5:

Solutions:

a) (-4, 2] - interval notation

{x | -4 < x ≤ 2} - set-builder notation 