1MA0 Higher June 2015 Paper 2 Q25
25 Solve the equation \(3x^2 + 4x - 12 = 0\)
Give your solutions correct to 2 decimal places. (3)
| Working | Answer | Mark | Notes |
|---|---|---|---|
| \(\dfrac{-4 \pm \sqrt{4^2 - 4 \times 3 \times -12}}{2 \times 3}\) | 1.44 and \(-2.77\) | 3 | M1 for substitution of \(a = 3\), \(b = 4\), \(c = -12\) into the formula (condone one sign error) or for completing the square M1 for \(\dfrac{-4 \pm \sqrt{160}}{6}\) or in simplified form A1 for answers in the ranges 1.43 to 1.45 and \(-2.76\) to \(-2.78\) |