Inverse of $f^{-1}(x)=x^5+2x^3+3x+1$ question Let $f$ be a one-to-one function whose inverse function is $f^{-1}(x)=x^5+2x^3+3x+1$.
Compute the value of $x_0$ such that $f(x_0)=1$.
I am confused as to what this question is asking me, particularly since I don't understand the subscript under the $x$ variable. 

$f^{-1}(x)=x^5+2x^3+3x+1$.
$f(f^{-1}(x))=f(x^5+2x^3+3x+1)$.
$f(f^{-1}(x))=x$  as function property

$x=f(x^5+2x^3+3x+1)$.  
$f(x^5+2x^3+3x+1)=x$
$f(x_0)=1$
You can see that $x=1$ so   $x_0=x^5+2x^3+3x+1$
$x_0=1^5+2.1^3+3.1+1=7$
