Foundation June 2022 Paper 1R Q21
21
(a) Expand \(\quad 3c^3(c + 4)\) (2)
(b)
(i) Factorise \(\quad x^2 + 8x - 9\) (2)
(ii) Hence, solve \(\quad x^2 + 8x - 9 = 0\) (1)
| Scheme | Marks |
|---|---|
| \(3c^4 + 12c^3\) | B2 |
| (2) |
Notes
B2: for \(3c^4 + 12c^3\)
(B1 for \(3c^4\) or \(12c^3\))
| Scheme | Marks |
|---|---|
| (i) | M1 |
| \((x + 9)(x - 1)\) | A1 |
| (ii) Answer: \(-9, 1\) | B1 |
| (3) | |
| (5 marks) |
Notes
M1: for \((x \pm 9)(x \pm 1)\)
or for \((x + a)(x + b)\) with \(ab = -9\) or \(a + b = 8\)
A1: for correct factors
B1: ft dep on factorising in the form \((x + p)(x + q)\)