Higher November 2017 Paper 1 Q14
14 The ratio \((y + x) : (y - x)\) is equivalent to \(k : 1\)
Show that \(y = \dfrac{x(k+1)}{k-1}\) (3)
| Working | Answer | Mark | Notes |
|---|---|---|---|
| \(y = \dfrac{x(k+1)}{k-1}\) | M1 | \(y + x = k(y - x)\) or \(\dfrac{y+x}{y-x} = k\) oe | |
| \({ky-y=x+kx}\) \({y(k-1)=x(1+k)}\) | M1 | For isolating \(x\) and \(y\) on opposite sides eg \(ky - y = x + kx\) | |
| A1 | Completing correct algebraic reasoning to reach conclusion |