This key facts covers Sign Rules Cheat Sheet within Factorising for GCSE Mathematics. Revise Factorising in Algebra for GCSE Mathematics with 12 exam-style questions and 3 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 12 of 12 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 12 of 12
Practice
12 questions
Recall
3 flashcards
Sign Rules Cheat Sheet
| Expression | Signs in Brackets |
|---|---|
| x² + bx + c (both positive) | (x + __)(x + __) |
| x² - bx + c (middle neg, end pos) | (x - __)(x - __) |
| x² + bx - c (end negative) | (x + __)(x - __) bigger number positive |
| x² - bx - c (end negative) | (x + __)(x - __) bigger number negative |
Q5 Factorise: x² + 7x + 10 [2 marks]
[1] 2 × 5 = 10, 2 + 5 = 7
[1] (x + 2)(x + 5)
Q6 Factorise: x² + x - 12 [2 marks]
[1] -3 × 4 = -12, -3 + 4 = 1
[1] (x - 3)(x + 4)
Q7 Factorise: x² - 8x + 12 [2 marks]
[1] -2 × -6 = 12, -2 + -6 = -8
[1] (x - 2)(x - 6)