There are a variety of ways line graphs can be used to clearly display complex information. Each axis is named by the quantity labelled on it. This might be \(x\) and \(y\), or time and temperature.

Parallel lines are a fixed distance apart and will never meet, no matter how long they are extended. Lines that are parallel have the same gradient. The graphs above, \(y = 2x + 1\) and \(y = 2x - 2\) ...