Let's try to analyze the behavior of the function
$$f(x) = -0.9x(x+1)(x-2).$$
First, let's start with just a graph of $f$ together with a graph of $y=x$. Have a look at that on either Desmos or on Easy Plot or even WolframAlpha (if you can figure out how to plot them both together).
- How many fixed points do you see?
- How many are attractive and how many repulsive?
I suppose you could try our cobweb tool to verify your conjectures.