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Course: Algebra I / Elementary Algebra
Topic: Linear Equations and Inequalities
Subtopic: Solving Compound Inequalities

Overview

Compound inequalities means to combine two or more inequalities together. There are three ways to do this. Two inequalities can be connected by an "and" (intersection ) which means that the final answer will be those numbers that are in both sets (the overlapping region). Two inequalities can be connected by an "or" (union ) which means that the final answer will be those numbers that are in one set or the other or both -- basically the answer will be both sets all lumped together. The third way to compound inequalities is the "double" kind which means that there are multiple inequalities in one statement like 4<2x-1<10. The key to solving double inequalities is simply to get x isolated in the middle. The final answers to all of these compound inequalities will usually be written in interval notation. Treat this section as an introduction to compound inequalities. This topic will be covered more thoroughly in a College Algebra class.

Objectives

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

Terminology

Define: compound linear inequality, intersection ∩, union ∪

Text Notes
Text: Intro & Inter Algebra for CS 3ed by Blitzer, sect. 9.1-9.4