Higher June 2018 Paper 4 Q9
9 The dimensions, in centimetres, of this rectangle are shown as algebraic expressions.
Not to scale
Work out the length and width of the rectangle. [6]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| 15 9 | 6 | B5 for [\(x\)=] 4.5 or \(4\frac{1}{2}\) and [\(y\) =] −0.5 or \(-\frac{1}{2}\) even given as answers OR B2 for \(5x - y - 8 = 3x + 5y + 4\) or \(3x + y - 4 = 2x - 6y - 3\) | accept 15 or 9 either way round for 6 marks |
| and M1dep for rearranging either equation correctly so that the \(x\)’s, \(y\)’s and numbers are combined in one of the equations | The next M1s are dep on B2 gained. For M1 need an equation with one \(x\) term, one \(y\) term and one number term and allow one numerical error e.g. \(2x - 6y = 12\) oe or \(x + 7y - 1 = 0\) oe . | ||
| and M1dep for multiplying one equation to equate coefficients of one variable | allow one numerical error e.g. \(2x - 6y = 12\) and \(2x + 14y = 2\) | ||
| and M1dep for the correct method to eliminate a variable If 0 scored SC1 for equating two adjacent sides e.g. \(5x - y - 8 = 2x - 6y - 3\) | allow one numerical error e.g. \(20y = -10\) | ||