Higher June 2019 Unit 1 Q15
15.
(a) Simplify \(\sqrt{45}\).
Circle your answer. [1]
Circle your answer. [1]
\(3\sqrt{5}\) \(3\sqrt{15}\) \(5\sqrt{3}\) \(9\sqrt{5}\) 22·5
(b) Evaluate \(\left(2\sqrt{7} - \sqrt{3}\right)^2\).
Simplify your answer. [2]
Simplify your answer. [2]
| Scheme | Marks | Comments |
|---|---|---|
| \(3\sqrt{5}\) | B1 |
| Scheme | Marks | Comments |
|---|---|---|
| \(4 \times \sqrt{49} - 2\sqrt{7 \times 3} - 2\sqrt{7 \times 3} + \sqrt{9}\) or \(4 \times 7 - 2\sqrt{21} - 2\sqrt{21} + 3\) or equivalent | M1 | Allow one incorrect term. \(\sqrt{7}\sqrt{7}\) is insufficient for \(\sqrt{49}\). \(\sqrt{3}\sqrt{3}\) is insufficient for \(\sqrt{9}\). Allow \(\sqrt{7}\sqrt{3}\) or \(\sqrt{3}\sqrt{7}\) for \(\sqrt{21}\). |
| \(31 - 4\sqrt{21}\) | A1 | \(\sqrt{7}\sqrt{3}\) or \(\sqrt{3}\sqrt{7}\) is insufficient for \(\sqrt{21}\). |