Higher November 2023 Paper 6 Q6
6 The area of this rectangle can be written as \(ax^2 + bx - 10\).
Not to scale
Find the values of \(a\), \(b\) and \(c\).
You must show your working. [5]
| Answer | Marks | Part marks and guidance | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| \(a = 3\), \(b = -13\), \(c = -5\) with correct working | 5 | Correct working requires evidence of at least one M1 | ||||||||
| M1 for \((3x + 2)(x + c)\) soi B1 for \(a = 3\) B1 for \(c = -5\) | Condone \(3x + 2 \times x + c\) as soi Grid method for expanding e.g.
M1 for shaded cells correct | |||||||||
| AND M1 for \(3c + 2\) or \(3 \times\) their \(c + 2\) either alone or as coefficients of \(x\) in a full or partial expansion B1 for \(b = -13\) | Accept \(x(3c + 2)\) and \(3cx + 2x\) ignore coefficient of \(x^2\) and constant Condone embedded answers for \(b\) or \(c\) provided they are not then contradicted on answer line e.g. B1 for \((x - 5)\) and B1 for \(-13x\) seen | |||||||||