Higher November 2016 Unit 1 Q12
12. Express \(\dfrac{3x}{3x+2} - \dfrac{2x}{2x+7}\) as a single fraction in its simplest form. [3]
| Scheme | Marks | Comments |
|---|---|---|
| \(3x(2x + 7) - 2x(3x + 2)\) as a numerator within a single fraction | M1 | Accept intention of brackets when working not shown e.g. \(6x^2 + 21x \;-\; 6x^2 + 4x\). |
| \((3x + 2)(2x + 7)\) as a denominator. | M1 | |
| \(17x \,/\, (3x + 2)(2x + 7)\) | A1 | C.A.O. If M1M1A1 awarded penalise further incorrect work −1. If no marks awarded then SC1 for sight of \(17x\). |