Finding the inverse of a function means to write the expression
[tex]f(x)=\ldots[/tex]
and to solve it for x.
In this case, we have
[tex]f(x)=x-1[/tex]
Adding 1 to both sides gives
[tex]f(x)+1=x[/tex]
So, the inverse of the function is
[tex]f^{-1}(x)=x+1[/tex]
