Higher November 2020 Paper 2 Q25
25 Factorise \(\quad 3x^2 + 11x - 20\) [2 marks]
| Answer | Mark | Comments |
|---|---|---|
| \((3x - 4)(x + 5)\) | B2 | oe product of brackets eg \((x + 5)(3x - 4)\) or \((3x - 4)(5 + x)\) or \(-(4 - 3x)(x + 5)\) B1 \((3x + a)(x + b)\) where \(ab = -20\) or \(a + 3b = 11\) or \(3x(x + 5) - 4(x + 5)\) or \(x(3x - 4) + 5(3x - 4)\) |
Additional guidance
| Ignore attempts to solve \(3x^2 + 11x - 20 = 0\) | |
| \((3x + 4)(x - 5)\) | B1 |
| \((3x + 4)(x + 5)\) | B0 |
| \((3x - 1)(x + 4)\) | B1 |
| \((3x + 1)(x - 4)\) | B0 |
| Condone multiplication signs between brackets for B2 eg \((3x - 4) \times (x + 5)\) | B2 |
| Condone multiplication signs between brackets for B1 eg \((3x - 1) \times (x + 20)\) | B1 |
| Condone missing final bracket eg1 \((3x - 4)(x + 5\) eg2 \((3x - 20)(x + 1\) | B2 B1 |
| Do not allow \(x3\) for \(3x\) etc |