A set of questions to practise the concept of y=mx + c including finding equations of lines with various clues (including just two points on the line). Simple start but some harder questions later. Also some questions to provoke deeper thinking towards the end. I like to ask the class to come up with their own 'True, False, Sometimes True' style questions as a useful and challenging extension. This can result in some excellent discussion amongst the class. No knowledge of perpendicular lines needed.