Higher November 2022 Paper 1 Q15
15 Show that \(\quad (3x + 4)(2x - 5) - 11x(x - 2) + 5(x^2 - 3x - 1) \quad\) simplifies to an integer. [4 marks]
| Answer | Mark | Comments |
|---|---|---|
| \(6x^2 + 8x - 15x - 20\) or \(6x^2 - 7x - 20\) | M1 | allow 4 terms with 3 correct or \(6x^2 - 7x + k\), where \(k\) is a non-zero number |
| \(-11x^2 + 22x\) or \(5x^2 - 15x - 5\) | M1 | |
| \(6x^2 + 8x - 15x - 20\) or \(6x^2 - 7x - 20\) and \(-11x^2 + 22x\) and \(5x^2 - 15x - 5\) | A1 | |
| \(6x^2 + 8x - 15x - 20\) or \(6x^2 - 7x - 20\) and \(-11x^2 + 22x\) and \(5x^2 - 15x - 5\) and \(-25\) | A1 |
Additional guidance
Allow terms seen in a grid
Sign errors cannot be recovered
Ignore equating the expression to zero