The line l1 l_1\,l1 has equation 12y+7x=1712y + 7x = 1712y+7x=17 The line l2 l_2\,l2 passes through the points (8,9)(8, 9)(8,9) and (−6,−15)(-6, -15)(−6,−15).
Determine, giving full reasons for your answer, whether lines l1 l_1\,l1 and l2 l_2\,l2 are parallel, perpendicular or neither.
260 exam-style questions on Edexcel A Level Maths Straight Line Graphs, covering 5.1 y = mx + c, 5.2 Equations of Straight Lines, 5.3 Parallel and Perpendicular Lines, 5.4 Length and Area, and 5.5 Modelling with Straight Lines. Each one has a worked solution and a mark scheme showing where the marks go.