Linear equations · Grade 8
In Grade 8 you learn: unknowns on both sides.
A linear equation has an unknown, usually x, with no powers — like 3x + 5 = 20. Solving it means finding the value that makes both sides equal. Think of a balance: whatever you do to one side, you must do to the other.
Key facts
- Do the same thing to both sides to keep the equation balanced.
- Undo the operations in reverse order: for 3x + 5 = 20, subtract 5 first, then divide by 3.
- If x is on both sides, subtract the smaller x term from both sides first.
- Check your answer by substituting it back into the original equation.
Worked examples
Example 1
Solve 4x − 7 = 21.
Answer: x = 7