| Exam Board | OCR |
|---|---|
| Module | C1 (Core Mathematics 1) |
| Marks | 8 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Straight Lines & Coordinate Geometry |
| Type | Perpendicular line through point |
| Difficulty | Moderate -0.8 This is a straightforward C1 coordinate geometry question requiring standard techniques: finding gradient from two points, converting to general form, and using the perpendicularity condition for lines. Both parts are routine textbook exercises with no problem-solving insight needed, making it easier than average but not trivial since it requires multiple steps and careful algebraic manipulation. |
| Spec | 1.03a Straight lines: equation forms y=mx+c, ax+by+c=01.03b Straight lines: parallel and perpendicular relationships |
7. The straight line $l$ passes through the point $P ( - 3,6 )$ and the point $Q ( 1 , - 4 )$.\\
(i) Find an equation for $l$ in the form $a x + b y + c = 0$, where $a , b$ and $c$ are integers.
The straight line $m$ has the equation $2 x + k y + 7 = 0$, where $k$ is a constant.\\
Given that $l$ and $m$ are perpendicular,\\
(ii) find the value of $k$.\\
\hfill \mbox{\textit{OCR C1 Q7 [8]}}