If f(x)=3x+1f(x) = 3x + 1f(x)=3x+1 and f−1(x)f^{-1}(x)f−1(x) is its inverse, what is the value of f−1(10)f^{-1}(10)f−1(10)?
x=3x = 3x=3
x=31x = 31x=31
x=2x = 2x=2
x=33x = 33x=33