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Knowunity Philippines
12/13/2025
Math
Solving linear equations in one variable - step by step guide
136
•
Dec 13, 2025
•
Step-by-Step Guide to Solving Linear Equations in One Variable
Knowunity Philippines
@knowunityphilippines
1 / 10
What Makes an Equation Linear?
You've probably solved equations before without realising they were linear equations! A linear equation has just one variable (like x or y) and that variable is never squared or cubed - it's always to the power of 1.
Think of these equations like a straight line on a graph (that's why they're called 'linear'). The basic form looks like this: ax + b = c, where a, b, and c are just numbers.
Here are some examples you might recognise: 2x + 5 = 11 or 3y - 7 = 14. Notice how the variable appears only once and isn't squared or in fractions.
Key Point: If you can write your equation as ax + b = c, you've got a linear equation - and that means you can solve it!
The Balance Method
Imagine an equation as a perfectly balanced scale - whatever you do to one side, you must do to the other side to keep it balanced. This is your golden rule for solving any linear equation.
Inverse operations are your best friends here. Addition undoes subtraction, and multiplication undoes division. If you see +5 on one side, subtract 5 from both sides. If you see ÷3, multiply both sides by 3.
Let's try 2x + 7 = 15: First, subtract 7 from both sides to get 2x = 8. Then divide both sides by 2 to get x = 4. Always check your answer by putting it back into the original equation!
Top Tip: The balance method never fails - just remember to do the same thing to both sides every single time.
Tackling Tricky Equations
When variables appear on both sides of an equation, don't panic! Just collect all the x terms on one side and all the numbers on the other side.
For equations with brackets, use the distributive property first. If you see 2, multiply both terms inside: 2x + 6. Then solve normally.
Fractions in equations might look scary, but there's a simple trick. Multiply everything by the bottom number of the fraction to clear it away. For x/3 + 2 = 5, multiply everything by 3 to get x + 6 = 15.
Remember: Take it step by step - simplify first, then move terms around, and finally isolate your variable.
Real-World Problem Solving
Linear equations help you solve actual problems you might face! Whether you're working out costs at a shop or calculating distances, the same problem-solving steps apply.
Start by reading carefully and deciding what your variable represents. If Maria buys notebooks for £15 each plus a £25 pen, and spends £85 total, then 15x + 25 = 85 tells you she bought 4 notebooks.
Transport problems work the same way. If a taxi charges £12 for the first 4km and £2 for each extra km, you can work out any journey cost using linear equations.
Success Strategy: Define your variable clearly, write your equation based on the story, solve it step by step, and always check your answer makes sense!
Avoiding Common Mistakes
The biggest mistake students make is forgetting the balance rule - always do the same operation to both sides! If you subtract 5 from the left side, you must subtract 5 from the right side too.
Sign errors trip up loads of students. When you move +7 from one side to the other, it becomes -7. Think of it as the term changing its sign as it crosses the equals sign.
When distributing, multiply the outside number by every term inside the brackets. So 3 becomes 3x + 12, not 3x + 4. Don't forget that second term!
Golden Rule: Always check your answer by substituting it back into the original equation - if both sides equal the same number, you're right!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the 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: Variable
Quadratic equations and functions: Forms and properties
Master the three forms of quadratic equations and their key properties
MathG9
Most popular content in Math
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
Step-by-Step Guide to Solving Linear Equations in One Variable
Knowunity Philippines
@knowunityphilippines
Linear equations are everywhere - from calculating how much change you'll get at the shops to working out travel distances. These simple but powerful mathematical tools help us solve real problems by finding unknown values using basic operations you already... Show more
What Makes an Equation Linear?
You've probably solved equations before without realising they were linear equations! A linear equation has just one variable (like x or y) and that variable is never squared or cubed - it's always to the power of 1.
Think of these equations like a straight line on a graph (that's why they're called 'linear'). The basic form looks like this: ax + b = c, where a, b, and c are just numbers.
Here are some examples you might recognise: 2x + 5 = 11 or 3y - 7 = 14. Notice how the variable appears only once and isn't squared or in fractions.
Key Point: If you can write your equation as ax + b = c, you've got a linear equation - and that means you can solve it!
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
The Balance Method
Imagine an equation as a perfectly balanced scale - whatever you do to one side, you must do to the other side to keep it balanced. This is your golden rule for solving any linear equation.
Inverse operations are your best friends here. Addition undoes subtraction, and multiplication undoes division. If you see +5 on one side, subtract 5 from both sides. If you see ÷3, multiply both sides by 3.
Let's try 2x + 7 = 15: First, subtract 7 from both sides to get 2x = 8. Then divide both sides by 2 to get x = 4. Always check your answer by putting it back into the original equation!
Top Tip: The balance method never fails - just remember to do the same thing to both sides every single time.
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
Tackling Tricky Equations
When variables appear on both sides of an equation, don't panic! Just collect all the x terms on one side and all the numbers on the other side.
For equations with brackets, use the distributive property first. If you see 2, multiply both terms inside: 2x + 6. Then solve normally.
Fractions in equations might look scary, but there's a simple trick. Multiply everything by the bottom number of the fraction to clear it away. For x/3 + 2 = 5, multiply everything by 3 to get x + 6 = 15.
Remember: Take it step by step - simplify first, then move terms around, and finally isolate your variable.
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
Real-World Problem Solving
Linear equations help you solve actual problems you might face! Whether you're working out costs at a shop or calculating distances, the same problem-solving steps apply.
Start by reading carefully and deciding what your variable represents. If Maria buys notebooks for £15 each plus a £25 pen, and spends £85 total, then 15x + 25 = 85 tells you she bought 4 notebooks.
Transport problems work the same way. If a taxi charges £12 for the first 4km and £2 for each extra km, you can work out any journey cost using linear equations.
Success Strategy: Define your variable clearly, write your equation based on the story, solve it step by step, and always check your answer makes sense!
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
Avoiding Common Mistakes
The biggest mistake students make is forgetting the balance rule - always do the same operation to both sides! If you subtract 5 from the left side, you must subtract 5 from the right side too.
Sign errors trip up loads of students. When you move +7 from one side to the other, it becomes -7. Think of it as the term changing its sign as it crosses the equals sign.
When distributing, multiply the outside number by every term inside the brackets. So 3 becomes 3x + 12, not 3x + 4. Don't forget that second term!
Golden Rule: Always check your answer by substituting it back into the original equation - if both sides equal the same number, you're right!
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
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
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
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
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
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the 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.
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Most popular content: Variable
Quadratic equations and functions: Forms and properties
Master the three forms of quadratic equations and their key properties
MathG9
Most popular content in Math
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user