Higher November 2018 Paper 1 Q19
19.
(a) Simplify \(\dfrac{3}{\sqrt{3}}\). [1]
(b) Write \(\sqrt{63} + \sqrt{175}\) in the form \(k\sqrt{7}\), where \(k\) is an integer. [2]
(c) Expand and simplify \(\left(4 - 2\sqrt{5}\right)\left(2 + \sqrt{5}\right)\). [2]
(d) Complete the following identity. [1]\[x^2 - 3 \equiv (x - \ldots\ldots)(x + \ldots\ldots)\]
| Scheme | Marks | Comments |
|---|---|---|
| \(\sqrt{3}\) | B1 |
| Scheme | Marks | Comments |
|---|---|---|
| \(8\sqrt{7}\) | B2 | Allow \(k = 8\); B1 for \(3\sqrt{7}\) or \(5\sqrt{7}\) seen |
| Scheme | Marks | Comments |
|---|---|---|
| \(-2\) | B2 | B1 for 3 out of 4 correct in \(8 + 4\sqrt{5} - 4\sqrt{5} - 2(5)\) or for sight of all 4 terms e.g. listed |
| Scheme | Marks | Comments |
|---|---|---|
| \((x - \sqrt{3})(x + \sqrt{3})\) | B1 | seen or implied |
| (6) |