0606/13 May/Jun 2025, Question 2: The Discriminant and Nature of Roots
Cambridge IGCSE Additional Mathematics 0606 · Paper 13 (Non-calculator) · Non-calculator · 4 marks
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The question, in short
Determine the values of k such that x² + 4kx + k + 3 = 0 has a repeated root.
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Solution · 4 marks
- 1Two equal roots: b² − 4ac = 0
- 2(4k)² − 4(k + 3) = 0
- 316k² − 4k − 12 = 0, i.e. 4k² − k − 3 = 0
- 4(4k + 3)(k − 1) = 0
- 5k = −3/4 or k = 1
Answerk = −3/4, 1
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Also searched as: 0606/13/M/J/25 · 0606_s25_qp_13 · 0606 s25 13 · question 2.
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