Intermediate November 2017 Unit 2 Q14
14.
(a) Rearrange the following formula to make \(x\) the subject.
Give your answer in its simplest form. [3]\[2(x + y) = 7y - 3\]
Give your answer in its simplest form. [3]\[2(x + y) = 7y - 3\]
(b) Write down the \(n\)th term of the following sequence. [2]
3, 6, 11, 18, 27, …
| Scheme | Marks | Comments |
|---|---|---|
| 14(a) \(2x + 2y = 7y - 3\) OR \(x + y = \dfrac{7y - 3}{2}\) | B1 | F.T. until 2nd error provided of equivalent difficulty. |
| \(2x = 5y - 3\) OR \(x = \dfrac{7y - 3}{2} - y\) | B1 | |
| \(x = \dfrac{5y - 3}{2}\) | B1 | Accept x= \(\dfrac{5y}{2} - \dfrac{3}{2}\) OR x = \(\dfrac{-5y + 3}{-2}\) OR x = 2½y − 1½ or equivalent. Must have ‘x = ‘. An answer of \(\dfrac{5y - 3}{2}\) gains B1B1B0 (missing ‘x =’) Mark final answer. |
| Scheme | Marks | Comments |
|---|---|---|
| \(n^2 + 2\) | B2 | Mark final answer. B1 for n2 ± …., not for n2 alone B0 for an2 ± ….. where a ≠ 1. |