Higher November 2021 Paper 2 Q12
12 Expand and simplify \((x - 2)(3x + 2)(2x + 3)\) (3)
| Answer | Mark | Mark scheme |
|---|---|---|
| \(6x^3 + x^2 - 20x - 12\) | M1 | for method to find the product of any two linear expressions (3 out of no more than 4 terms correct with correct signs or 4 correct terms ignoring signs), eg. \(6x^2 + 9x + 4x + 6\) or \(3x^2 + 2x - 6x - 4\) or \(2x^2 + 3x - 4x - 6\) |
| M1 | for method of multiplying out remaining products, half of which are correct (ft their first product), eg. \(6x^3 + 13x^2 - 12x^2 + 6x - 26x - 12\) | |
| A1 | cao |
Additional guidance
Note that, for example, \(6x^2 + 13x\) or \(13x + 6\) are regarded as three terms in the expansion of \((3x + 2)(2x + 3)\) (corrected from the printed mark scheme: it says \((x - 2)(3x + 2)\), but these terms come from \((3x + 2)(2x + 3)\))
First product must be quadratic but need not be simplified or may be simplified incorrectly.