Higher June 2024 Paper 1R Q12
12 Solve the simultaneous equations
\[\begin{aligned} 4x + 3y &= 9.6 \\ 6x + 5y &= 16.8 \end{aligned}\]Show clear algebraic working.
(4)
| Scheme | Marks |
|---|---|
eg \(\begin{aligned} 12x + 9y &= 28.8 \\ -\;\;12x + 10y &= 33.6 \end{aligned}\) or \(\begin{aligned} 20x + 15y &= 48 \\ -\;\;18x + 15y &= 50.4 \end{aligned}\) or eg \(4x + 3\left(\dfrac{16.8 - 6x}{5}\right) = 9.6\) or \(6\left(\dfrac{9.6 - 3y}{4}\right) + 5y = 16.8\) | M1 |
| \(x = -1.2\) oe or \(y = 4.8\) oe | A1 |
| M1 | |
| Working required Answer: \(x = -1.2\) oe and \(y = 4.8\) oe | A1 |
| (4) | |
| (4 marks) |
Notes
M1: for multiplication of one or both equation(s) with correct operation selected (allow one arithmetic error) (if + or – is not shown then assume it is the operation that at least 2 of the 3 terms have been calculated for) or correct rearrangement of one equation with substitution into the second
A1: dep on M1
M1: (dep on M1) for substitution of found variable
or
repeating the steps in first M1 for the second variable
A1: dep on M1