Foundation January 2020 Paper 2R Q21
21 Solve the simultaneous equations
\(\begin{aligned} 3x + 5y &= 6 \\ 7x - 5y &= -11 \end{aligned}\)
Show clear algebraic working.
(3)
| Scheme | Marks |
|---|---|
| (adding) \(10x = -5\) or \(\begin{aligned} 21x + 35y &= 42 \\ 21x - 15y &= -33 \end{aligned}\) then \(50y = 75\) | M1 |
| Working required Answer: \(x = -0.5\) oe | A1 |
| Working required Answer: \(y = 1.5\) oe | A1 |
| (3) | |
| (3 marks) |
Notes
M1: Correct method to eliminate \(x\) or \(y\): coefficients of \(x\) or \(y\) the same and correct operator to eliminate selected variable
or correct substitution for \(x\) or \(y\) into 2nd equation
A1: Both A marks dep on M1