1MA0 Higher November 2014 Paper 2 Q20
20 Solve \(3x^2 - 5x - 1 = 0\)
Give your solutions correct to 3 significant figures. (3)
| Answer | Mark | Notes |
|---|---|---|
| 1.85 and \(-0.180\) | 3 | M1 for \(\dfrac{--5 \pm \sqrt{-5^2 - 4 \times 3 \times -1}}{2 \times 3}\) (condone one sign error) M1 for \(\dfrac{5 \pm \sqrt{37}}{6}\) (=1.8 to 1.85 or \(-0.18\) to \(-0.181\)) A1 for answers in the ranges 1.8 to 1.85, and \(-0.18\) to \(-0.181\) |