Answer
$\frac{3}{x}$
Work Step by Step
We are given the expression $3x^{-1}$
$3x^{-1}=3(x^{-1})=3\times\frac{1}{x}=\frac{3}{x}$
In general, $a^{-n}=\frac{1}{a^{n}}$ (where a is a nonzero real number and n is a positive integer).
The 3 and the x are not in parentheses, so only the x (the base of the exponent) is evaluated by the exponent.