How to compose two functions? I have three functions: 

$$f(x) = x+1 ,\; g(x) = x - 1 ,\; h(x) = 2x$$

I want to find $g\circ f$ such that $g(f(x))$, which equals $(x+1)-1=x$ but how? 
I don't understand the steps.
Also, I want to find $h\circ f$ which equals $h(f(x)) = 2x-1$ but I dont know how to get that answer either.
Thanks

$g(f(x))$ means you substitute $f(x)$ in wherever you see $x$ in $g(x)$, therefore we get $g(f(x)) = (x+1)-x = x$
Performing the same for $h(f(x))$, we get $h(f(x)) = 2(x+1) = 2x + 2$
