Inequality Pacman
If you want to describe a point you use coordinates (2,5), for lines you use functions: y=-3x+2, but what about whole "regions"? One way is to use "inequalities". An "inequal" function is one in which you define the y-coordinate as being "greater than: >", "greater than OR equal to: ", "less than: <", or "less than OR equal to: ". There are many ways to remember which way round the sign should be, one of which is...