4MA0 Higher January 2017 Paper 3 Q9
9 Simplify \(\;(2x + 3)^2 - (2x + 3)(x - 5)\)
Give your answer in the form \(\;ax^2 + bx + c\)
(3)
| Scheme | Marks |
|---|---|
| \(4x^2 + 6x + 6x + 9\) or \(4x^2 + 12x + 9\) | M1 |
| \(2x^2 - 10x + 3x - 15\) or \(2x^2 - 7x - 15\) | M1 |
| \(2x^2 + 19x + 24\) | A1 |
| (3) | |
| (3 marks) |
Notes
M1: for at least 3 terms correct in expansion of first pair of brackets
M1: for at least 3 terms correct in expansion of second pair of brackets or
all 4 terms correct ignoring signs
allow \(-2x^2 - 7x - 15\)
Alternative method
| Scheme | Marks |
|---|---|
| \((2x + 3)[(2x + 3) - (x - 5)]\) | M1 |
| \((2x + 3)(x + 8)\) | M1 |
| \(2x^2 + 19x + 24\) | A1 |