AlgebraExam Tips

Common Mistakes to Avoid

Part of Quadratic ExpressionsGCSE Mathematics

This exam tips covers Common Mistakes to Avoid within Quadratic Expressions for GCSE Mathematics. Revise Quadratic Expressions in Algebra for GCSE Mathematics with 12 exam-style questions and 22 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 7 of 7 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.

Topic position

Section 7 of 7

Practice

12 questions

Recall

22 flashcards

Common Mistakes to Avoid

  • Sign errors: (x - 3)(x + 2) ≠ x² + x - 6
    Correct: x² - x - 6 (careful with the middle term!)
  • Forgetting the x² term: Always check your first term is x²
  • Wrong factor pairs: For x² + 7x + 10, don't use (x + 1)(x + 10)
    Check: 1 + 10 = 11 ≠ 7
  • Perfect square confusion: (x + 3)² ≠ x² + 9
    Correct: (x + 3)² = x² + 6x + 9
  • Missing negative signs: When one factor is negative, be extra careful with signs throughout

Keep building this topic

Read this section alongside the surrounding pages in Quadratic Expressions. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for Quadratic Expressions

Expand (x + 5)².

  • A. x² + 25
  • B. x² + 5x + 25
  • C. x² + 10x + 25
  • D. x² + 10x + 5
1 markfoundation

Explain how to recognise whether x² + 12x + 36 is a perfect square trinomial, and write it in factorised form.

2 markshigher

Quick Recall Flashcards

Expand (x + 2)(x + 5)
x² + 5x + 2x + 10 = x² + 7x + 10 (Using FOIL: First + Outer + Inner + Last)
Expand (x + 6)(x - 4)
x² - 4x + 6x - 24 = x² + 2x - 24 (Be careful with negative signs!)

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