If you are studying GCSE you need to be able to draw and recognise graphs of simple functions, both straight lines and curves. If you are at college your computer might have software on it such as Omnigraph. If you are at home you can download free open source software that does the same job, called “Graph”. You can read more about Graph and download it here. When you have downloaded it experiment with different functions and see what happens to the graph. To enter x² you have to use x^2.
Here are some ideas of functions to try.
y=x, y=2x, y=3x, y=4x etc
y=x+1, y=x+2, y=x+3 etc
y=-x, y=-2x, y=-3x etc
y=x-1, y=x-2, y=x-3 etc
y=x^2, y=x^2+1, y=x^2+2 etc
y=x^2+x, y=x^2 +2x, y=x^2 +3x etc
y=x^3, y=x^3 +1, y=x^3 +2 etc