4MA0 Higher January 2014 Paper 4R Q20
20 Express \(\;\dfrac{4}{x - 1} - \dfrac{3}{x + 1}\;\) as a single fraction.
Give your answer as simply as possible.
(3)
| Scheme | Marks |
|---|---|
| \(\dfrac{4(x + 1) - 3(x - 1)}{(x + 1)(x - 1)}\) | M1 |
| \(\dfrac{4x + 4 - 3x + 3}{(x + 1)(x - 1)}\) | M1 |
| \(\dfrac{x + 7}{x^2 - 1}\) | A1 |
| (3) | |
| (3 marks) |
Notes
M1: For expressing both fractions correctly with a common denominator. Allow as two separate fractions.
M1: For removing brackets correctly in a correct single fraction. Allow \(x^2 - 1\) in denominator.
A1: Allow \(\dfrac{x + 7}{(x + 1)(x - 1)}\)