Study Notes
Factorisation involves rewriting an algebraic expression by taking out common factors, which is the reverse process of expansion.
- Factorisation — the process of expressing an algebraic expression as a product of its factors. Example: x^2 + x = x(x+1)
- Common Factor — a factor that is common to all terms in an expression. Example: In 8x^2y + 6xy^2, 2xy is the common factor.
- Quadratic Factorisation — rewriting a quadratic expression in the form ax^2 + bx + c as a product of two binomials. Example: x^2 + 11x + 24 = (x+3)(x+8)
Exam Tips
Key Definitions to Remember
- Factorisation is the reverse of expansion.
- A common factor is a factor shared by all terms in an expression.
Common Confusions
- Forgetting to take out the highest common factor (HCF) first.
- Mixing up the steps for factorising quadratics with simple factorisation.
Typical Exam Questions
- How do you factorise 32p^2q - 4pq^2? Answer: 4pq(8p - q)
- How do you factorise 36x^3 + 24x^5? Answer: 12x^3(3 + 2x^2)
- How do you factorise 2x^2 + 7x + 5? Answer: (2x + 5)(x + 1)
What Examiners Usually Test
- Ability to identify and factor out the common factor.
- Correctly factorising quadratic expressions into two binomials.