2025 DSS PRELIMS P1 Q3

2025 DSS PRELIMS P1 Q3

Secondary 4

3 marks

Explain why \(3x^2+15x+20\) cannot be smaller than 1.[3]

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Answer:\(3x^2+15x+20=3\left(x+\dfrac{5}{2}\right)^2+\dfrac{5}{4}\geq\dfrac{5}{4}>1\), so it cannot be smaller than \(1\).

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