4400 Higher June 2007 Paper 3 Q9
9
(a) Solve \(5x - 4 = 2x + 7\) (2)
(b) Solve \(\dfrac{7 - 2y}{4} = 2y + 3\) (4)
| Scheme | Marks |
|---|---|
| \(5x - 2x = 7 + 4\) | M1 |
| \(\frac{11}{3}\), \(3\frac{2}{3}\) oe | A1 |
| (2) |
Notes
M1: for correct rearrangement
A1: Also accept 2 or more d.p. rounded or truncated e.g. 3.66, 3.67
| Scheme | Marks |
|---|---|
\(4 \times \dfrac{7 - 2y}{4}\) or \(7 - 2y\) \(= 4(2y + 3)\) | M1 |
| \(7 - 2y = 8y + 12\) or simpler | M1 |
| \(10y = -5\) | A1 |
| \(-\frac{1}{2}\) oe | A1 |
| (4) | |
| (6 marks) |
Notes
M1: for clear intention to multiply both sides by 4 or a multiple of 4
For example, award for \(4 \times \dfrac{7 - 2y}{4}\) or \(7 - 2y\) \(= 4 \times 2y + 3\) or \(8y + 3\) or \(2y + 3 \times 4\) or \(2y + 12\)
M1: for correct expansion of brackets (usually \(8y + 12\)) or for correct rearrangement of correct terms e.g. \(8y + 2y = 7 - 12\)
A1: for reduction to correct equation of form \(ay = b\)