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Linear Equations

Year 8 📊 Algebra  Solve linear equations with unknowns on both sides.

⚖️ Solving Linear Equations

Linear equations have no powers higher than 1. Use inverse operations, working in reverse BODMAS order.

Example: Solve $5(2x - 3) = 25$ → expand: $10x - 15 = 25$ → add 15: $10x = 40$ → divide by 10: $x = 4$

↔️ Variables on Both Sides

Collect all variable terms on one side and number terms on the other.

  1. Expand any brackets.
  2. Add or subtract to get all $x$ terms on one side.
  3. Add or subtract to move all numbers to the other side.
  4. Divide by the coefficient of $x$.
Example: Solve $3x + 7 = x + 15$ → subtract $x$: $2x + 7 = 15$ → subtract 7: $2x = 8$ → $x = 4$

📐 Equations with Fractions

Multiply every term by the LCM of the denominators to clear all fractions.

Example: Solve $\frac{x+1}{3} = \frac{2x-1}{5}$ → multiply through by 15: $5(x+1) = 3(2x-1)$ → $5x+5 = 6x-3$ → $x = 8$
💡 Always check your answer by substituting back into the original equation.
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