Contents

Introduction

Properties

Linear Inequalities 

1  2

Quadratic Inequalities 

Cubic Inequalities

Fractional Inequalities

Modulus Inequalities

Problem Solving

Quiz 

Algebra Main Page

Cubic Inequalities

Example 1

Solve

(x - 2)(x + 1)(2x + 1)(x - 3) 0

Step 1: Draw a number line for the first x (ignore the rest) and note down the regions where it's positive or negative

Step 2: Repeat for the rest of the x

Step 3: Multiply the '+' and '-' in each column together

Step 4: If the question wants <0, choose the overall '-' region, if the question wants >0, choose the '+' region

Step 5: Write the region down

-1 x <½   or   2 x < 3

Example 2

Solve

The solution is x < -2 or -1< x < 4