You can also plot multiple expressions and functions on the same graph using the plot() command. Instead of specifying a single function as your first parameter, create a list of functions using square brackets.
Similarly, instead of specifying a single colour, specify a list of colours using square brackets. The order of the functions matches the order of the colours.
If you need several complicated graphs to display at once, you may wish to explore the potential of the display() command, found in Assigning Plots and the display() Command.