๐Ÿ”ฎ Algebra Realm ยท Equations

Linear equations

Linear equations focuses on how to solve equations where the unknown has power one by peeling away operations while preserving balance. In this lesson, focus on an equation is a balanced statement.

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Understand Linear equations

Linear equations focuses on how to solve equations where the unknown has power one by peeling away operations while preserving balance. In this lesson, focus on an equation is a balanced statement.

An equation is a balanced statement. Undo operations in a controlled order while performing the same change to both sides. For linear equations, the final written answer should make that exact relationship visible rather than hiding it inside an unexplained result.

Start here

Linear equations: An equation is a balanced statement. Substitute the proposed solution into the original equation and verify that both sides match. Keep the linear equations representation visible until the final line.

Picture the idea

Move algebra tiles across a balance scale and record each legal inverse operation as a solver step. Use the model to explain one change you notice while working on linear equations.

Check as you go

Substitute the proposed solution into the original equation and verify that both sides match. Write that check beside the final linear equations answer.

Key vocabulary

equationinverse operationbalanceunknownsolutionlinearequations

Rules and key facts

3x + 7 = 22 gives 3x = 15, then x = 5.

  • Simplify either side if needed.
  • Choose an inverse operation that removes one obstacle around the unknown.
  • Apply the same operation to both sides.
  • Continue until the unknown is isolated, then substitute to check. Record the check explicitly for linear equations.

Step-by-step method

  1. Simplify either side if needed.
  2. Choose an inverse operation that removes one obstacle around the unknown.
  3. Apply the same operation to both sides.
  4. Continue until the unknown is isolated, then substitute to check. Record the check explicitly for linear equations.

What you need first

  • Recognise the vocabulary: equation, inverse operation, balance.
  • Be able to explain the purpose of linear equations before calculating.
  • Keep the relevant values, units and representation visible while you work.

Real-world use

  • Unknown prices
  • Formula calculations

Visual / interactive

See the idea, then move it around

Skip to Practice

Move algebra tiles across a balance scale and record each legal inverse operation as a solver step. Use the model to explain one change you notice while working on linear equations.

Interactive maths model Connected to this topic; move controls, check outputs, then earn XP only from verified actions.
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Worked examples

Examples, methods and exam thinking

Level 1 ยท Foundation

Understand the idea with small numbers, one representation and one clear step.

Level 2 ยท Secure

Use the standard Year 8 method with mixed examples and normal wording.

Level 3 ยท Challenge

Handle multi-step or less familiar questions and explain choices.

Level 4 ยท Exam-style

Solve a worded question, show reasoning, check accuracy and write a final sentence.

Foundation example

Build confidence

Given information: Linear equations โ€” Solve 3x + 2 = 8. Method choice: use the linear equations method and show each step with the stated values. Calculation or reasoning: Subtract 2: 3x = 6. Divide by 3: x = 2. Final answer: 2. Check: substitute or compare with the original information to confirm the result fits the question.

  1. Simplify either side if needed.
  2. Choose an inverse operation that removes one obstacle around the unknown.
  3. Apply the same operation to both sides.
Secure example

Use the normal method

Given information: Linear equations โ€” Solve 3x + 14 = 44. Method choice: use the linear equations method and show each step with the stated values. Calculation or reasoning: Subtract 14: 3x = 30. Divide by 3: x = 10. Final answer: 10. Check: substitute or compare with the original information to confirm the result fits the question.

Check: Substitute into the original equation, including its full left side.

Challenge example

Stretch the idea

Given information: Linear equations โ€” Solve 3x + 13 = 34. Method choice: use the linear equations method and show each step with the stated values. Calculation or reasoning: Subtract 13: 3x = 21. Divide by 3: x = 7. Final answer: 7. Check: substitute or compare with the original information to confirm the result fits the question.

Try explaining why each step works before checking the answer.

Exam-style example

Show your reasoning

Given information: Linear equations โ€” Solve 3x + 12 = 24. Method choice: use the linear equations method and show each step with the stated values. Calculation or reasoning: Subtract 12: 3x = 12. Divide by 3: x = 4. Final answer: 4. Check: substitute or compare with the original information to confirm the result fits the question.

Exam tip: Show the same operation on both sides on separate lines.

Common mistakes

  • Changing one side only. This is a key trap when answering linear equations questions.
  • Skipping a line and losing a negative sign or denominator.

How to check your answer

Substitute the proposed solution into the original equation and verify that both sides match. Write that check beside the final linear equations answer.

Extension challenge

Create a linear equations problem with a tempting incorrect answer. Solve it, apply the check, and explain exactly where the incorrect method breaks down.

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Use balance battle controls to solve three checked linear equations rounds. Solve at least two of three marked rounds and use feedback to correct any error.

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Study cards

Core idea

Linear equations: An equation is a balanced statement. Substitute the proposed solution into the original equation and verify that both sides match. Keep the linear equations representation visible until the final line.

Tap to mark reviewed
Key vocabulary

equation ยท inverse operation ยท balance ยท unknown ยท solution ยท linear ยท equations

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Rules

Simplify either side if needed. Choose an inverse operation that removes one obstacle around the unknown. Apply the same operation to both sides. Continue until the unknown is isolated, then substitute to check. Record the check explicitly for linear equations.

Tap to mark reviewed
Formula / fact

3x + 7 = 22 gives 3x = 15, then x = 5.

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Foundation example

Given information: Linear equations โ€” Solve 3x + 2 = 8. Method choice: use the linear equations method and show each step with the stated values. Calculation or reasoning: Subtract 2: 3x = 6. Divide by 3: x = 2. Final answer: 2. Check: substitute or compare with the original information to confirm the result fits the question.

Tap to mark reviewed
Secure example

Given information: Linear equations โ€” Solve 3x + 14 = 44. Method choice: use the linear equations method and show each step with the stated values. Calculation or reasoning: Subtract 14: 3x = 30. Divide by 3: x = 10. Final answer: 10. Check: substitute or compare with the original information to confirm the result fits the question.

Tap to mark reviewed
Challenge example

Given information: Linear equations โ€” Solve 3x + 13 = 34. Method choice: use the linear equations method and show each step with the stated values. Calculation or reasoning: Subtract 13: 3x = 21. Divide by 3: x = 7. Final answer: 7. Check: substitute or compare with the original information to confirm the result fits the question.

Tap to mark reviewed
Exam-style example

Given information: Linear equations โ€” Solve 3x + 12 = 24. Method choice: use the linear equations method and show each step with the stated values. Calculation or reasoning: Subtract 12: 3x = 12. Divide by 3: x = 4. Final answer: 4. Check: substitute or compare with the original information to confirm the result fits the question.

Tap to mark reviewed
Common mistake

Changing one side only. This is a key trap when answering linear equations questions.

Tap to mark reviewed
Exam tip

For linear equations, show the key representation before the final calculation. Use this final check: Substitute the proposed solution into the original equation and verify that both sides match.

Tap to mark reviewed
Real-world use

Unknown prices, Formula calculations

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Checklist

I can explain linear equations, use the method, check for mistakes, and answer an exam-style question.

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Flashcards

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Help for Linear equations

Use this whenever a question feels confusing. Nothing here is locked.

Simple explanation

Linear equations: An equation is a balanced statement. Substitute the proposed solution into the original equation and verify that both sides match. Keep the linear equations representation visible until the final line.

Think of linear equations as a careful model: make the important values visible, change one thing at a time, and use the check to prove the answer fits.

Step-by-step breakdown

  1. Simplify either side if needed.
  2. Choose an inverse operation that removes one obstacle around the unknown.
  3. Apply the same operation to both sides.
  4. Continue until the unknown is isolated, then substitute to check. Record the check explicitly for linear equations.

Hint 1

Start by naming the given information and the exact result required for linear equations.

Hint 2

Simplify either side if needed.

Full worked solution

Given information: Linear equations โ€” Solve 3x + 2 = 8. Method choice: use the linear equations method and show each step with the stated values. Calculation or reasoning: Subtract 2: 3x = 6. Divide by 3: x = 2. Final answer: 2. Check: substitute or compare with the original information to confirm the result fits the question.

Method: Simplify either side if needed. โ†’ Choose an inverse operation that removes one obstacle around the unknown. โ†’ Apply the same operation to both sides. โ†’ Continue until the unknown is isolated, then substitute to check. Record the check explicitly for linear equations.

Common mistake warning

Changing one side only. This is a key trap when answering linear equations questions.

Choose a support button above when you need a nudge.

Mastery milestones

Badges reward learning, not locked clicking

  • I can explain linear equations in my own words.
  • I can use these words accurately: equation, inverse operation, balance.
  • I can follow the 4-step method without guessing.
  • I can avoid this mistake: Changing one side only.
  • I can apply this check: Substitute the proposed solution into the original equation and verify that both sides match.
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