This study notes covers Worked Example 2: Negative Constant within Solving Quadratics for GCSE Mathematics. Revise Solving Quadratics in Algebra for GCSE Mathematics with 15 exam-style questions and 12 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 5 of 7 in this topic. Use this study notes to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 5 of 7
Practice
15 questions
Recall
12 flashcards
Worked Example 2: Negative Constant
Solve: x² - 2x - 15 = 0
Step 1 Factorise
Need: multiply to -15, add to -2
Numbers: -5 and +3 (check: -5 × 3 = -15, -5 + 3 = -2 ✓)
(x - 5)(x + 3) = 0
Step 2 Solve each bracket
Either x - 5 = 0 → x = 5
Or x + 3 = 0 → x = -3
Answer:
x = 5 or x = -3