help!

\(f(x)=\color{red}\frac{1}{1-x}\\ so\\ f(f(x))=\frac{1}{1-\color{red}\frac{1}{1-x}}\)

 

Now you can simplify that and then find the next function yourself.

If you have questions you can ask but don't just say "I don't get it" or the equivalent.

 

 

Other answers please respect that this is a teaching answer and do not answer over the top of it.