Given f(x)=3x−1f(x) = 3x - 1f(x)=3x−1, find f−1(x)f^{-1}(x)f−1(x).
13x−1\frac{1}{3x-1}3x−11
3x+13x+13x+1
x−13\frac{x-1}{3}3x−1
x+13\frac{x+1}{3}3x+1