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Year 8 · Patterns & Algebra
Add and subtract expressions
Polynomials add and subtract by collecting like terms, and multiply by expanding every pair.
How to do it
- Add: combine x² with x², x with x, numbers with numbers.
- Subtract: change every sign in the second bracket, then add.
- Multiply: each term times each term, then collect.
Worked example
(2x² + 3x − 1) + (x² − 5x + 4)
x²: 2 + 1. x: 3 − 5. Numbers: −1 + 4
3x² − 2x + 3
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Watch outSubtracting a negative term adds it.
Practise Add and subtract expressions properly
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