This study notes covers Common Mistakes within Expanding Brackets for GCSE Mathematics. Revise Expanding Brackets in Algebra for GCSE Mathematics with 14 exam-style questions and 3 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 7 of 13 in this topic. Use this study notes to connect the idea to the wider topic before moving on to questions and flashcards.
Common Mistakes
✗ 3(x + 4) = 3x + 4
✓ 3(x + 4) = 3x + 12 (multiply BOTH terms)
✗ -2(x - 3) = -2x - 6
✓ -2(x - 3) = -2x + 6 (neg × neg = pos)
✗ 5(x + 2) = 5x + 2
✓ 5(x + 2) = 5x + 10 (don't forget the second term!)
Practice Questions
Q1 Expand: 2(x + 4) [1 mark]
[1] 2 × x + 2 × 4 = 2x + 8
Q2 Expand: 5(3x - 7) [2 marks]
[1] 5 × 3x = 15x
[1] 5 × (-7) = -35
Answer: 15x - 35
Q3 Expand: -4(x - 3) [2 marks]
[1] -4 × x = -4x
[1] -4 × (-3) = +12
Answer: -4x + 12
Q4 Expand: 3x(2x + 5) [2 marks]
[1] 3x × 2x = 6x²
[1] 3x × 5 = 15x
Answer: 6x² + 15x
Practice questions for Expanding Brackets
Which expression is equivalent to 3(x + 2)?
Expand -2(3x - 5)
Quick recall flashcards
Sign Rules
Positive × Positive = Positive | Negative × Negative = Positive | Different signs = Negative
Expansion Rule
a(b + c) = ab + ac - multiply EVERY term inside by the term outside