Higher November 2020 Paper 3 Q28
28 Line A has equation \(\quad y = 4x - 1\)
Line B is
perpendicular to line A
and
passes through the point (8, 5)
Work out the coordinates of the point where line B intersects the \(x\)-axis. [4 marks]
| Answer | Mark | Comments |
|---|---|---|
| \(-\dfrac{1}{4}\) or \(-1 \div 4\) | M1 | oe |
| \(5 = \text{their } {-\dfrac{1}{4}} \times 8 + c\) or \(c = 7\) or \(y - 5 = -\dfrac{1}{4}(x - 8)\) | M1dep | oe \(y = -\dfrac{1}{4}x + 7\) implies M2 |
| \(-\dfrac{1}{4}x + 7 = 0\) or \((x =)\ 28\) | M1dep | oe |
| (28, 0) | A1 | SC2 (−12, 0) or (6.75, 0) |
Additional guidance
| Answer (0, 28) is A0 but may score M marks if working seen | |
| (−12, 0) from using the gradient of the perpendicular as ¼ | SC2 |
| (6.75, 0) from using the gradient of the perpendicular as 4 | SC2 |