9.130. $\left|\frac{3 x+1}{x-3}\right|<3$.

9.130. $\left|\frac{3 x+1}{x-3}\right|<3$. 

The above text has been translated into English while retaining the original formatting and line breaks. However, the mathematical expression itself is unchanged as it is a universal notation.
## Solution.

The inequality is equivalent to a system of two inequalities

$\left\{\begin{array}{l}\frac{3 x+1}{x-3}-3\end{array} \Leftrightarrow\left\{\begin{array}{l}\frac{3 x+1}{x-3}-30\end{array} \Leftrightarrow\left\{\begin{array}{l}\frac{10}{x-3}0\end{array} \Leftrightarrow\right.\right.\right.$

$\Leftrightarrow\left\{\begin{array}{l}x-30\end{array} \Leftrightarrow x<\frac{4}{3}\right.$.

Answer: $x \in\left(-\infty ; \frac{4}{3}\right)$.