Quadratic Inequalities
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Higher June 2025 Paper 2 Q21
21 Solve \((3x - 1)(5x + 2) \lt 0\) (2)
Mark scheme| Answer | Mark | Mark scheme |
|---|
| \(-\dfrac{2}{5} \lt x \lt \dfrac{1}{3}\) | B2 | for \(-\dfrac{2}{5} \lt x \lt \dfrac{1}{3}\) oe |
| (B1 | For correct critical values of \(-\dfrac{2}{5}\) and \(\dfrac{1}{3}\) oe) |
Additional guidance
May be given as two separate inequalities
Accept \(-0.4\) and 0.33 (or better)
Higher June 2017 Paper 3 Q21
21 Here is a sketch of \(\quad y = \mathrm{f}(x) \quad\) where \(\mathrm{f}(x)\) is a quadratic function.
The graph intersects the \(x\)-axis where \(\quad x = -2.5 \quad\) and \(\quad x = 1\)
Not drawn accurately
Circle the solution of \(\;\mathrm{f}(x) \gt 0\) [1 mark]
- \(x \lt -2.5\;\) or \(\;x \gt 1\)
- \(x \gt -2.5\;\) or \(\;x \gt 1\)
- \(-2.5 \lt x \lt 1\)
- \(x \gt -2.5\;\) or \(\;x \lt 1\)
Mark scheme| Answer | Mark | Comments |
|---|
| \(-2.5 \lt x \lt 1\) | B1 | |
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