Higher November 2020 Paper 1 Q28
28 Factorise fully \(\quad 144 - 4x^2\) [2 marks]
| Answer | Mark | Comments |
|---|---|---|
| \(4(6 + x)(6 - x)\) or \(-4(x + 6)(x - 6)\) | B2 | oe with full factorisation B1 \((12 + 2x)(12 - 2x)\) or \(2(6 + x)(12 - 2x)\) or \((12 + 2x)2(6 - x)\) or \(2(6 + x)2(6 - x)\) or \(4(36 - x^2)\) oe |
Additional guidance
| \(2(72 - 2x^2)\) | B0 |
| Condone multiplication signs for B1 or B2 eg1 \(4 \times (6 + x) \times (6 - x)\) eg2 \((12 + 2x) \times (12 - 2x)\) eg3 \((12 + 2 \times x) \times (12 - x \times 2)\) | B2 B1 B1 |
| Condone missing final bracket eg1 \(4(6 + x)(6 - x\) eg2 \((12 + 2x)(12 - 2x\) | B2 B1 |
| Do not allow \(x2\) for \(2x\) | |
| Ignore attempts to solve \(144 - 4x^2 = 0\) |