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Mastering Algebraic Expressions: A-Level Pure Maths Chapter 1

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A

Ann

03/12/2025

Maths

Chapter 1 - Algebraic expressions

266

3 Dec 2025

3 pages

Mastering Algebraic Expressions: A-Level Pure Maths Chapter 1

A

Ann

@ann_jznv

Algebraic expressions are the building blocks of advanced maths, and... Show more

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Page 2
Page 3
1 / 3
Index laws
Pours of same base simplify:
• amxa^ =am+n
• am ÷ an = am-n
• (am)^
= amn
• (ab)^ = a^bn
Eg
1- Algebitur expressions
Q 95-5x3
3x

Index Laws and Expanding Brackets

Index laws are your best mates when simplifying expressions with powers. Remember these four golden rules: am×an=am+na^m \times a^n = a^{m+n}, am÷an=amna^m \div a^n = a^{m-n}, (am)n=amn(a^m)^n = a^{mn}, and (ab)n=anbn(ab)^n = a^n b^n.

When you're dividing algebraic fractions, split them up term by term. For example, 9x55x33x\frac{9x^5 - 5x^3}{3x} becomes 9x53x5x33x=3x453x2\frac{9x^5}{3x} - \frac{5x^3}{3x} = 3x^4 - \frac{5}{3}x^2.

Expanding brackets means multiplying every term in one bracket by every term in another. With multiple brackets like (2x+5y)(3xy)(2x+y)(2x + 5y)(3x - y)(2x + y), work systematically - expand two brackets first, then multiply by the third. Keep track of like terms and combine them at the end.

Top Tip: When expanding complex expressions, write out each step clearly to avoid silly mistakes - your future self will thank you!

Index laws
Pours of same base simplify:
• amxa^ =am+n
• am ÷ an = am-n
• (am)^
= amn
• (ab)^ = a^bn
Eg
1- Algebitur expressions
Q 95-5x3
3x

Factorising and Index Rules

Factorising is basically expanding backwards - you're looking for common factors and patterns. Always start by taking out the highest common factor, like pulling out the 3 from 15x2+42x915x^2 + 42x - 9 to get 3(5x2+14x3)3(5x^2 + 14x - 3).

For quadratics, you need two numbers that multiply to give the constant term and add to give the middle coefficient. In x2+9x+20x^2 + 9x + 20, you want numbers that multiply to 20 and add to 9 - that's 4 and 5, giving (x+4)(x+5)(x+4)(x+5).

Negative and fractional indices follow the same rules but with twists: am=1ama^{-m} = \frac{1}{a^m}, a0=1a^0 = 1, and amn=amna^{\frac{m}{n}} = \sqrt[n]{a^m}. When solving equations like 27x3=1x27\sqrt[3]{x} = \frac{1}{x}, rewrite everything using fractional indices first.

Remember: Factorising completely means you can't factor any further - always double-check your answer!

Index laws
Pours of same base simplify:
• amxa^ =am+n
• am ÷ an = am-n
• (am)^
= amn
• (ab)^ = a^bn
Eg
1- Algebitur expressions
Q 95-5x3
3x

Surds and Rationalising Denominators

Surds are square roots that can't be simplified to whole numbers, and they follow specific manipulation rules: ab=a×b\sqrt{ab} = \sqrt{a} \times \sqrt{b} and ab=ab\sqrt{\frac{a}{b}} = \frac{\sqrt{a}}{\sqrt{b}}.

To simplify surds like 75\sqrt{75}, look for perfect square factors. Since 75=25×375 = 25 \times 3, we get 75=53\sqrt{75} = 5\sqrt{3}. You can then combine like terms: 5323=335\sqrt{3} - 2\sqrt{3} = 3\sqrt{3}.

Rationalising denominators gets rid of surds from the bottom of fractions. For simple cases like 1a\frac{1}{\sqrt{a}}, multiply top and bottom by a\sqrt{a}. For expressions like 1a+b\frac{1}{a + \sqrt{b}}, multiply by the conjugate (ab)(a - \sqrt{b}) - this creates a difference of squares that eliminates the surd.

Pro Strategy: Always multiply by the conjugate when you see addition or subtraction with surds in the denominator!



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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

Best app on earth! no words because it’s too good

Thomas R

iOS user

Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.

Basil

Android user

This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.

Rohan U

Android user

I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.

Xander S

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now

Paul T

iOS user

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

Best app on earth! no words because it’s too good

Thomas R

iOS user

Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.

Basil

Android user

This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.

Rohan U

Android user

I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.

Xander S

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now

Paul T

iOS user

 

Maths

266

3 Dec 2025

3 pages

Mastering Algebraic Expressions: A-Level Pure Maths Chapter 1

A

Ann

@ann_jznv

Algebraic expressions are the building blocks of advanced maths, and mastering them now will make A-level topics so much easier. This guide covers the essential skills you'll use constantly: index laws, expanding brackets, factorising, and working with surds.

Index laws
Pours of same base simplify:
• amxa^ =am+n
• am ÷ an = am-n
• (am)^
= amn
• (ab)^ = a^bn
Eg
1- Algebitur expressions
Q 95-5x3
3x

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Index Laws and Expanding Brackets

Index laws are your best mates when simplifying expressions with powers. Remember these four golden rules: am×an=am+na^m \times a^n = a^{m+n}, am÷an=amna^m \div a^n = a^{m-n}, (am)n=amn(a^m)^n = a^{mn}, and (ab)n=anbn(ab)^n = a^n b^n.

When you're dividing algebraic fractions, split them up term by term. For example, 9x55x33x\frac{9x^5 - 5x^3}{3x} becomes 9x53x5x33x=3x453x2\frac{9x^5}{3x} - \frac{5x^3}{3x} = 3x^4 - \frac{5}{3}x^2.

Expanding brackets means multiplying every term in one bracket by every term in another. With multiple brackets like (2x+5y)(3xy)(2x+y)(2x + 5y)(3x - y)(2x + y), work systematically - expand two brackets first, then multiply by the third. Keep track of like terms and combine them at the end.

Top Tip: When expanding complex expressions, write out each step clearly to avoid silly mistakes - your future self will thank you!

Index laws
Pours of same base simplify:
• amxa^ =am+n
• am ÷ an = am-n
• (am)^
= amn
• (ab)^ = a^bn
Eg
1- Algebitur expressions
Q 95-5x3
3x

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Factorising and Index Rules

Factorising is basically expanding backwards - you're looking for common factors and patterns. Always start by taking out the highest common factor, like pulling out the 3 from 15x2+42x915x^2 + 42x - 9 to get 3(5x2+14x3)3(5x^2 + 14x - 3).

For quadratics, you need two numbers that multiply to give the constant term and add to give the middle coefficient. In x2+9x+20x^2 + 9x + 20, you want numbers that multiply to 20 and add to 9 - that's 4 and 5, giving (x+4)(x+5)(x+4)(x+5).

Negative and fractional indices follow the same rules but with twists: am=1ama^{-m} = \frac{1}{a^m}, a0=1a^0 = 1, and amn=amna^{\frac{m}{n}} = \sqrt[n]{a^m}. When solving equations like 27x3=1x27\sqrt[3]{x} = \frac{1}{x}, rewrite everything using fractional indices first.

Remember: Factorising completely means you can't factor any further - always double-check your answer!

Index laws
Pours of same base simplify:
• amxa^ =am+n
• am ÷ an = am-n
• (am)^
= amn
• (ab)^ = a^bn
Eg
1- Algebitur expressions
Q 95-5x3
3x

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Surds and Rationalising Denominators

Surds are square roots that can't be simplified to whole numbers, and they follow specific manipulation rules: ab=a×b\sqrt{ab} = \sqrt{a} \times \sqrt{b} and ab=ab\sqrt{\frac{a}{b}} = \frac{\sqrt{a}}{\sqrt{b}}.

To simplify surds like 75\sqrt{75}, look for perfect square factors. Since 75=25×375 = 25 \times 3, we get 75=53\sqrt{75} = 5\sqrt{3}. You can then combine like terms: 5323=335\sqrt{3} - 2\sqrt{3} = 3\sqrt{3}.

Rationalising denominators gets rid of surds from the bottom of fractions. For simple cases like 1a\frac{1}{\sqrt{a}}, multiply top and bottom by a\sqrt{a}. For expressions like 1a+b\frac{1}{a + \sqrt{b}}, multiply by the conjugate (ab)(a - \sqrt{b}) - this creates a difference of squares that eliminates the surd.

Pro Strategy: Always multiply by the conjugate when you see addition or subtraction with surds in the denominator!

We thought you’d never ask...

What is the Knowunity AI companion?

Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.

Where can I download the Knowunity app?

You can download the app from Google Play Store and Apple App Store.

Is Knowunity really free of charge?

That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.

Most popular content: Algebraic Manipulation

Most popular content in Maths

Most popular content

Can't find what you're looking for? Explore other subjects.

Students love us — and so will you.

4.9/5

App Store

4.8/5

Google Play

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

Best app on earth! no words because it’s too good

Thomas R

iOS user

Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.

Basil

Android user

This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.

Rohan U

Android user

I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.

Xander S

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now

Paul T

iOS user

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

Best app on earth! no words because it’s too good

Thomas R

iOS user

Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.

Basil

Android user

This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.

Rohan U

Android user

I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.

Xander S

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now

Paul T

iOS user