June 2016 Paper 2 Q11
11 The \(x^2\) term in the expansion of \(\quad (3x + 4)(x^2 + px + 5) \quad\) is \(\ -23x^2\)
Work out the value of \(p\). [3 marks]
| Answer | Mark | Comments |
|---|---|---|
| \(4x^2\) or \(3px^2\) or \(4 + 3p\) | M1 | May be seen in an expansion or a grid Allow unsimplified eg \(3x \times px\) |
| their \(4(x^2)\) + their \(3p(x^2) = -23(x^2)\) | M1dep | Correct or ft their expansion ft is equating their terms in \(x^2\) to \(-23x^2\) Must be at least two terms with at least one linear term in \(p\) Allow unsimplified eg \(3x \times px + 4x^2 = -23x^2\) |
| \(-9\) | A1 |
Additional guidance
| In this question, only consider terms in \(x^2\) | |
| If only one term in \(x^2\) the maximum mark is M1 | |
| \(4 + 3p = -23\) followed by \(7p = -23\) | M1 M1 A0 |