Foundation November 2024 Paper 1 Q26
26 Solve \(x^2 - 2x - 15 = 0\) (3)
| Answer | Mark | Mark scheme |
|---|---|---|
| \(x = 5\), \(x = -3\) | M1 | for factorisation eg \((x \pm 3)(x \pm 5)\) or \((x + a)(x + b)\) where \(ab = -15\) or \(a + b = -2\) or for substitution into quadratic formula eg \(\dfrac{--2 \pm \sqrt{(-2)^2 - 4 \times 1 \times -15}}{2 \times 1}\) oe |
| M1 | for \((x + 3)(x - 5)\) or for \(\dfrac{2 \pm \sqrt{64}}{2}\) | |
| A1 | cao |
Additional guidance
Condone one sign error in substitution into quadratic formula.