4MA0 Foundation June 2015 Paper 2R Q22
22
(a) Expand \(5(2p - 3)\) (1)
(b) Expand and simplify fully \((n + 8)(n - 5)\) (2)
(c) \(y = x^3 - kx + 5\)
Work out the value of \(k\) when \(y = 6\) and \(x = -2\) (3)
Work out the value of \(k\) when \(y = 6\) and \(x = -2\) (3)
| Scheme | Marks |
|---|---|
| \(10p - 15\) | B1 |
| (1) |
Notes
B1: Accept \(10 \times p - 15\)
| Scheme | Marks |
|---|---|
| \(n^2 + 8n - 5n - 40\) | M1 |
| \(n^2 + 3n - 40\) | A1 |
| (2) |
Notes
M1: Three correct terms (out of four) or four terms correct except for signs.
A1: Do not isw.
| Scheme | Marks |
|---|---|
| \(6 = (-2)^3 - k(-2) + 5\) or \(6 = -8 + 2k + 5\) | M1 |
Eg \(6 + 8 - 5 = 2k\) or \(-2k = -8 + 5 - 6\) or \(9 = 2k\) or \(-9 = -2k\) or \(k = \dfrac{(-2)^3 - 6 + 5}{-2}\) or \(-k = \dfrac{6 - (-2)^3 - 5}{-2}\) or \(-k = -4.5\) | M1 |
| 4.5 | A1 |
| (3) | |
| Total 6 marks |
Notes
M1: For correct substitution
Allow omission of brackets.
M1: For correctly isolating \(2k\) or \(-2k\) or \(k\) or \(-k\) in a correct equation.
A1: Accept \(4\dfrac{1}{2}\), \(\dfrac{9}{2}\)