Algebra II/Trig MA4300
1-6 EXTEND – INTERVAL NOTATION
Date: ________________
When solving linear inequalities, we have expressed answers several ways: graphing, inequality notation
(e.g., x £ -5 ), and set-builder notation (e.g., {x| x £ -5 }. Another way to express a solution is using
interval notation.
In interval notation, there are only 5 symbols to know:
* Open: parentheses ( ) – endpoint is not included
* Closed: brackets [ ] – endpoint is included
* Positive Infinity ∞
* Negative Infinity -∞
* Union Sign 
Below is a list of websites (linked on SchoolWires) that show how to write solutions to inequalities using
interval notation. Choose two sites to read. Then complete the examples below.
1.
2.
3.
4.
Algebra 2 Textbook (Online @connected) p. 40
Regents Prep Website: http://www.regentsprep.org/Regents/math/ALGEBRA/AP1/IntervalNot.htm
Idmind http://id.mind.net/~zona/mmts/miscellaneousMath/intervalNotation/intervalNotation.html
Connexions: http://cnx.org/content/m13596/latest/
Write the solutions shown in the graphs in inequality and interval notation.
1) EXAMPLE
Write in Inequality notation
x ³ -4
Write in interval notation.
é -4, +¥
ë
)
2)
Write in Inequality notation
Write in interval notation.
Algebra II/Trig MA4300
Date: ________________
3)
Write in Inequality notation
Write in interval notation.
Write in Inequality notation
Write in interval notation.
Write in Inequality notation
Write in interval notation.
Write in Inequality notation
Write in interval notation.
Write in Inequality notation
Write in interval notation.
4)
5)
6)
7)