4MA0 Foundation January 2017 Paper 2 Q20
20 Solve the simultaneous equations
\[\begin{aligned} 5x - 2y &= 33 \\ 5x + 8y &= 18 \end{aligned}\]Show clear algebraic working.
(3)
| Scheme | Marks |
|---|---|
| Eg \(8y - -2y = 18 - 33\) or \(10y = -15\) or \(-2y - 8y = 33 - 18\) or \(-10y = 15\) or \(25x = 150\) or \(5x + 4(5x - 33) = 18\) or \(33 + 2y + 8y = 18\) or \(18 - 8y - 2y = 33\) | M1 |
| Eg \(5 \times 6 - 2y = 33\) or \(5 \times 6 + 8y = 18\) or \(5x - 2 \times -1.5 = 33\) or \(5x + 8 \times -1.5 = 18\) | M1 |
| \(x = 6,\ y = -1.5\) | A1 |
| (3) | |
| (3 marks) |
Notes
M1: For a correct method to find an equation in \(x\) or \(y\). Allow one arithmetical error.
M1: For a correct substitution
Dep on first M1awarded
A1: oe
dep on M1