Higher November 2022 Paper 4 Q22
22 Solve algebraically.
\[x^2 + y^2 = 18\]\[y = x - 6\] [5]| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| Some algebraic working leading to an answer of 3 −3 | 5 | M1 for e.g. \(x^2 + (x - 6)^2 = 18\) M1 for expanding their square term e.g. \(x^2 - 12x + 36\) M1 for \(2x^2 - 12x + 18 = 0\) or better M1 for [2]\((x - 3)^2\) or \((2x - 6)(x - 3)\) If 0 scored SC2 for correct answers with no algebraic working | condone one error in expanding brackets simplifying to \(ax^2 - bx + c\) e.g. solving their quadratic equation by e.g. factors or quadratic formula Note : apply scheme to substitution for \(x\) e.g. M1 for \((y + 6)^2 + y^2 = 18\) etc |