Solving Inequalities

Here we will learn about solving inequalities including how to solve linear inequalities, identify integers in the solution set and represent solutions on a number line.

There are also solving inequalities worksheets based on Edexcel, AQA and OCR exam questions, along with further guidance on where to go next if you’re still stuck.

What is solving inequalities?

Solving inequalities is where we calculate the values that an unknown variable can be in an inequality.

Solving inequalities is similar to solving equations, but where an equation has one unique solution, an inequality has a range of solutions.

To do this we need to balance the inequality in the same way as we would when solving an equation. Solutions can be integers or decimals, positive or negative numbers.

What is solving inequalities?

What is solving inequalities?

Solving an equation

\[\begin 2x+1&=9\\ 2x&=8\\ x&=4 \end\]

4 is the only solution to this equation.

Solving an inequality

x can be any value that is less than 4

Multiplying and dividing by a negative number

This changes the direction of the inequality sign.

\[\begin 1 – 2x&< 9\\ -2x&< 8\\ x&>-4 \end\]

x can be any value that is greater than -4

How to solve inequalities

In order to solve inequalities:

  1. Rearrange the inequality so that all the unknowns are on one side of the inequality sign.
  2. Rearrange the inequality by dividing by the x coefficient so that ‘x’ is isolated.
  3. Write your solution with the inequality symbol.

Explain how to solve inequalities

Explain how to solve inequalities

Solving inequalities worksheet

Solving inequalities worksheet

Solving inequalities worksheet

Get your free solving inequalities worksheet of 20+ questions and answers. Includes reasoning and applied questions.

Solving inequalities worksheet

Solving inequalities worksheet

Solving inequalities worksheet

Get your free solving inequalities worksheet of 20+ questions and answers. Includes reasoning and applied questions.

Related lessons on inequalities

Solving inequalities is part of our series of lessons to support revision on inequalities. You may find it helpful to start with the main inequalities lesson for a summary of what to expect, or use the step by step guides below for further detail on individual topics. Other lessons in this series include:

Solving linear inequalities examples

Example 1: solving linear inequalities

  1. Rearrange the inequality so that all the unknowns are on one side of the inequality sign.

In this case you are subtracting ‘6’ from both sides.

2 Rearrange the inequality by dividing by the x coefficient so that ‘x’ is isolated.

In this case you need to divide both sides by 4 .

3 Write your solution with the inequality symbol.

Any value less than 5 satisfies the inequality

Example 2: solving linear inequalities

Rearrange the inequality so that all the unknowns are on one side of the inequality sign.

In this case you need to add ‘4’ to both sides.

\[\begin 5x-4&\geq26\\ 5x&\geq30\\ \end\]

Rearrange the inequality by dividing by the x coefficient so that ‘x’ is isolated.

In this case you need to divide both sides by 5 .

\[\begin 5x-4&\geq26\\ 5x&\geq30\\ x&\geq6\\ \end\]

Write your solution with the inequality symbol.

Any value greater than or equal to 6 satisfies the inequality

Example 3: solving linear inequalities with brackets

Rearrange the inequality so that all the unknowns are on one side of the inequality sign.

Let’s start by expanding the bracket

Then we need to add ‘12’ to both sides.

\[\begin 3x-12&\leq12\\ 3x&\leq24\\ \end\]

Rearrange the inequality by dividing by the x coefficient so that ‘x’ is isolated.

In this case you need to divide both sides by 3 .

\[\begin 3x-12&\leq12\\ 3x&\leq24\\ x&\leq8\\ \end\]

Write your solution with the inequality symbol.

Any value less than or equal to 8 satisfies the inequality

Example 4: solving linear inequalities with unknowns on both sides

Rearrange the inequality so that all the unknowns are on one side of the inequality sign.

In this case you need to subtract ‘2x’ from both sides.

\[\begin 5x-6&>2x+15\\ 3x-6&>15\\ \end\]

Rearrange the inequality so that ‘x’ s are on one side of the inequality sign and numbers on the other.

In this case you need to add ‘6’ to both sides.

\[\begin 3x-6&>15\\ 3x&>21\\ \end\]

Rearrange the inequality by dividing by the x coefficient so that ‘x’ is isolated.

In this case you need to divide both sides by 3 .

\[\begin 3x&>21\\ x&>7\\ \end\]

Write your solution with the inequality symbol.

Any value greater than 7 satisfies the inequality

Example 5: solving linear inequalities with fractions

Rearrange the inequality to eliminate the denominator.

In this case you need to multiply both sides by 5 .

\[\begin \frac\]

Rearrange the inequality so that ‘x’ s are on one side of the inequality sign and numbers on the other.

In this case you need to subtract ‘3’ from both sides

\[\begin \frac\]

Write your solution with the inequality symbol.

Any value less than 7 satisfies the inequality

Example 6: solving linear inequalities – non integer solutions

Rearrange the inequality so that all the unknowns are on one side of the inequality sign.

In this case you need to subtract ‘1’ from both sides.

\[\begin 6x+1&\geq4\\ 6x&\geq3\\ \end\]

Rearrange the inequality by dividing by the x coefficient so that ‘x’ is isolated.

In this case you need to divide both sides by 6 .

\[\begin 6x+1&\geq4\\ 6x&\geq3\\ x&\geq\frac\\ \end\]

This can be simplified to \frac or the decimal equivalent.

Write your solution with the inequality symbol.

Any value less than \frac satisfies the inequality

Example 7: solving linear inequalities and representing solutions on a number line

Represent the solution on a number line

Rearrange the inequality so that ‘x’ s are on one side of the inequality sign and numbers on the other.

In this case you need to add ‘7’ to both sides.

Rearrange the inequality by dividing by the x coefficient so that ‘x’ is isolated.

In this case you need to divide both sides by 2 .

Represent your solution on a number line.

Any value less than 6 satisfies the inequality. An open circle is required at 6 and the value lower than 6 indicated with an arrow.

Example 8: solving linear inequalities with negative x coefficients

Rearrange the inequality so that ‘x’ s are on one side of the inequality sign and numbers on the other.

In this case you need to subtract ‘1’ from both sides.

\[\begin 1 – 2x &\]

Rearrange the inequality by dividing by the x coefficient so that ‘x’ is isolated.

In this case you need to divide both sides by negative 2 .

\[\begin 1 – 2x&\]

Change the direction of the inequality sign.

Because you divided by a negative number, you also need to change the direction of the inequality sign.

Example 9: solving linear inequalities and listing integer values that satisfy the inequality

List the integer values that satisfy

Rearrange the inequality so that all the unknowns are on one side of the inequality sign.

In this case you need to subtract ‘1’ from each part.

List the integer values satisfied by the inequality.

2 is not included in the solution set. 7 is included in the solution set. The integers that satisfy this inequality are:

Example 10: solving linear inequalities and listing integer values that satisfy the inequality

List the integer values that satisfy

Rearrange the inequality so that all the unknowns are on one side of the inequality sign.

In this case you need to divide each part by ‘4’ .

\[\begin 7\leq4 x \leq20\\ \frac\leq x \leq5\\ \end\]

List the integer values satisfied by the inequality.

\frac<7> \leq x \leq5

\frac is included in the solution set but it is not an integer. The first integer higher is ‘2’ . 5 is also included in the solution set. The integers that satisfy this inequality are:

Example 11: solving linear inequalities and representing the solution on a number line

List the integer values that satisfy

Rearrange the inequality so that all the unknowns are on one side of the inequality sign.

In this case you need to subtract ‘5’ from each part.

Rearrange the inequality so that ‘x’ is isolated. In this case you need to divide each part by 2.

Represent the solution set on a the number line

-4 is not included in the solution set so requires an open circle. 1 is included in the solution set so requires a closed circle. Put a solid line between the circles to indicate all the values that satisfy the solution set.

Common misconceptions

  • Solutions as inequalities

Not including the inequality symbol in the solution is a common mistake. An inequality has a range of values that satisfy it rather than a unique solution so the inequality symbol is essential

Errors can be made with solving equations and inequalities by not applying inverse operations or not balancing the inequalities. Working should be shown step-by-step with the inverse operations applied to both sides of the inequality.

Practice solving inequalities questions

GCSE Quiz False

GCSE Quiz False

GCSE Quiz False

GCSE Quiz True

2. Solve 4x-3\geq25

GCSE Quiz False

GCSE Quiz True

GCSE Quiz False

GCSE Quiz False

\begin 4x-3&\geq25\\ 4x&\geq28\\ x&\geq7\\ \end

3. Solve 2(x-5)\leq8

GCSE Quiz False

GCSE Quiz False

GCSE Quiz True

GCSE Quiz False

\begin 2(x-5)&\leq8\\ 2x-10&\leq8\\ 2x&\leq18\\ x&\leq9\\ \end

4. Solve 6x – 5 > 4x + 1

GCSE Quiz True

GCSE Quiz False

GCSE Quiz False

GCSE Quiz False

\begin 6x-5&>4x+1\\ 2x-5&>1\\ 2x&>6\\ x&>3\\ \end

GCSE Quiz False

GCSE Quiz True

GCSE Quiz False

GCSE Quiz False

\begin \frac>6\\ x-4&>12\\ x&>16\\ \end

6. Solve 8x+1\geq3

GCSE Quiz False

GCSE Quiz False

GCSE Quiz False

GCSE Quiz True

\begin 8x+1&\geq3\\ 8x&\geq2\\ x&\geq\frac\\ x&\geq\frac\\ \end

7. Represent the solution on a number line 5x – 2 < 28

GCSE Quiz False

GCSE Quiz False

GCSE Quiz True

GCSE Quiz False

An open circle is required and all values less than 6 indicated.

8. Solve 2 – 3x > 14

GCSE Quiz False

GCSE Quiz True

GCSE Quiz False

GCSE Quiz False

\begin 2- 3x&>14\\ -3x&>12 \\ x&

Change the direction of the inequality sign as you have divided by a negative number

9. List the integer values that satisfy 2

GCSE Quiz True

GCSE Quiz False

GCSE Quiz False

GCSE Quiz False

-1 is not included in the solution set as is greater than -1 .
2 is included in the solution set as x is less than or equal to 2 .

10. List the integer values that satisfy 4\leq3x\leq21

1, 2, 3, 4, 5, 6, 7

GCSE Quiz False

GCSE Quiz False

1, 2, 3, 4, 5, 6

GCSE Quiz False

2, 3, 4, 5, 6, 7

GCSE Quiz True

\begin 4\leq3 x \leq21\\ \frac\leq x \leq7\\ \end

The first integer greater than \frac is 2 .
7 is included in the solution set as x is less than or equal to 7 .

11. List the integer values that satisfy -4<3x+2\leq5

GCSE Quiz False

GCSE Quiz False

GCSE Quiz True

-3, -2, -1, 0, 1, 2, 3, 4, 5

GCSE Quiz False

-2 is not included in the solution set as x is greater than -2 .
1 is included in the solution set as x is less than or equal to 1 .

Solving inequalities GCSE questions

1. John’s solution to 2x + 5 > 17 is shown on the number line

Is John’s solution correct?
Explain your reasoning.

(2 marks)

Show answer

Correctly solves the inequality

(1)

No, correct solution is x > 6

Indicates ‘no’ with correct reason or represents correct inequality on the number line

(1)

2. (a) Solve 4x+1\leq3x-2
(b) Represent your solution to (a) on the number line

(4 marks)

Show answer

(a)
Correct attempt at solving, for example eliminating ‘x’ . x+1\leq-2

(1)

Correct solution x\leq-3

(1)

(b)
‘-3’ or their value indicated on the number line with a closed circle

(1)

Correct inequality or their inequality shown on the number line with aa closed circle and values on the left side of the circle indicated with an arrow.

(1)

3. (a) Solve 5x – 1 > 9
(b) Write down the smallest integer that satisfies 5x – 1 > 9

(3 marks)

Show answer

(a)
Correct attempt at solving: 5x > 10

(1)

Correct solution: x > 2

(1)

(b)
Correct solution: 3

(1)

Learning checklist

You have now learned how to:

The next lessons are

  • Sequences
  • Functions in algebra
  • Laws of indices

Still stuck?

Prepare your KS4 students for maths GCSEs success with Third Space Learning. Weekly online one to one GCSE maths revision lessons delivered by expert maths tutors.

GCSE Benefits

Find out more about our GCSE maths tuition programme.

UK flag

Maths Interventions

  • Primary Maths Tutoring
  • Secondary Maths Tutoring
  • Year 3-5 Tutoring Programmes
  • Year 6 & SATs Tutoring Programmes
  • KS3 Tutoring Programmes
  • GCSE Tutoring Programmes
  • How it works
  • Pricing
  • Case studies
  • Tutoring FAQs

Policies

  • Data Protection & Privacy Policy
  • Cookies Policy
  • Terms of service
  • GDPR Compliance
  • Safeguarding children
  • Anti slavery policy
  • Complaints Procedure

Popular Blogs

  • SATs Results 2023
  • Maths Games
  • Online Tutoring
  • Long Division Method
  • Teaching Strategies
  • 2D and 3D Shapes
  • BODMAS or BIDMAS?
  • Division
  • Multiplication
  • Times Tables

Quick Links

  • GCSE Maths Revision
  • Maths Intervention Programmes
  • Online Maths Tuition
  • Maths Tuition
  • One To One Tuition
  • Primary School Tuition
  • School Tutors
  • Online Maths Tutors
  • Primary Maths Tutors
  • GCSE Maths Tutors
  • Online GCSE Maths Tutors

Company

  • About us
  • Careers
  • Blog
  • Insight – Girls and Mathematics
  • Insight – What Maths Do We Need
  • Insight – Maths and Careers

Popular GCSE maths guides

  • GCSE maths past papers
  • GCSE maths questions
  • GCSE maths topics
  • Simultaneous equations
  • Nth term
  • Circle theorems
  • Factorising

© 2024 Third Space Learning. All rights reserved.
Third Space Learning is the trading name of Virtual Class Ltd

We use essential and non-essential cookies to improve the experience on our website. Please read our Cookies Policy for information on how we use cookies and how to manage or change your cookie settings.Accept

Privacy & Cookies Policy

Privacy Overview

This website uses cookies to improve your experience while you navigate through the website. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. We also use third-party cookies that help us analyze and understand how you use this website. These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies. But opting out of some of these cookies may affect your browsing experience.

Always Enabled

Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.

Non-necessary

Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.