Course: Elementary Algebra
Topic: Linear Equations and Inequalities
Subtopic: Set and Interval Notation


An infinite set of numbers (eg. all Real numbers greater than or equal to 1) can be represented in three different ways:

  1. Graphing the set on a number line
  2. Writing the set in inequality notation, eg. x≥1
  3. Writing the set in interval notation, eg. [1,+∞)
When graphing on a number line, watch when to use "open" vs. "closed" circles on the endpoints. Inequality notation is pretty straight forward. Interval notation is the most commonly used method so learn it well.


By the end of this topic you should know and be prepared to be tested on:


Terms you should be able to define: set, solution set, inequality sign, inequality notation, set-builder notation, interval notation, open interval, closed interval

Text Notes

When studying your textbook for this lesson here are a few things to watch.