For example, this graph shows the inequality \(x \textless -1\). This can be seen as there is a dashed line at \(x = -1\), and the region where the \(x\) coordinates are less than -1 is shaded.

text{change in l}} = £/l\). The gradient shows the cost per litre. Petrol costs £1.15 per litre. The graph crosses the vertical axis at (0, 0). This is known as the intercept. It shows that if ...