4MA0 Higher January 2016 Paper 4R Q20
20 Express \(\dfrac{3}{x + 2} - \dfrac{6}{2x + 5}\) as a single fraction.
Simplify your answer.
(3)
| Scheme | Marks |
|---|---|
| \(\dfrac{3(2x + 5) - 6(x + 2)}{(x + 2)(2x + 5)}\) | M1 |
| \(\dfrac{6x + 15 - 6x - 12}{(x + 2)(2x + 5)}\) | M1 |
| \(\dfrac{3}{(x + 2)(2x + 5)}\) | A1 |
| (3) |
Notes
M1: For expressing both fractions correctly with a common denominator. Allow as two separate fractions.
Condone one error in numerator expansion.
M1: For removing brackets correctly in a correct single fraction. Allow denominator to be expanded or 2 brackets.
A1: \(\dfrac{3}{2x^2 + 9x + 10}\) or