Higher November 2021 Paper 1 Q13
13. Make \(y\) the subject of this formula. [4]
\[x + y = \frac{wy + 7}{3}\]| Scheme | Marks | Comments |
|---|---|---|
| FT if of equivalent difficulty until 2nd error | ||
| \(3(x + y) = wy + 7\) or \(3x + 3y = wy + 7\) oe | B1 | Clears the fraction |
| \(3y - wy = 7 - 3x\) or \(3x - 7 = wy - 3y\) oe | B1 | FT; collects terms |
| \(y(3 - w) = 7 - 3x\) or \(3x - 7 = y(w - 3)\) oe | B1 | FT; factorises; allow omission of closing bracket |
| \(y = \dfrac{7 - 3x}{3 - w}\) or \(y = \dfrac{3x - 7}{w - 3}\) oe | B1 | FT; divides |
| (4) |