June 2025 Paper 1 Q15
15 \(\quad (x - 3)(x + 4)(x + p) \equiv x^3 + qx^2 + rx + 24\)
Work out the values of \(p\), \(q\) and \(r\). [3 marks]
| Answer | Mark | Comments |
|---|---|---|
| \(p = -2\) | B1 | |
| \(q = -1\) | B1ft | ft their \(p + 1\) or correct answer |
| \(r = -14\) | B1ft | ft their \(p - 12\) or correct answer |
Additional guidance
| Fully correct expansion (could be seen in a grid) if no other marks scored \(x^3 + px^2 + x^2 + px - 12x - 12p\) oe | B1 |