9.020. $y=\sqrt{5-x-\frac{6}{x}}$.

The above text is translated into English as follows, retaining the original text's line breaks and format:

9.020. $y=\sqrt{5-x-\frac{6}{x}}$.
## Solution.

$$
D(y): 5-x-\frac{6}{x} \geq 0,\left\{\begin{array}{l}
x\left(x^{2}-5 x+6\right) \leq 0, \\
x \neq 0
\end{array},\left\{\begin{array}{l}
x(x-2)(x-3) \leq 0 \\
x \neq 0
\end{array}\right.\right.
$$

Using the interval method, we find $x<0$ or $2 \leq x \leq 3$.

![](https://cdn.mathpix.com/cropped/2024_05_22_fa9db84b44b98ec0a5c7g-523.jpg?height=146&width=608&top_left_y=1627&top_left_x=318)

Answer: $\quad x \in(-\infty ; 0) \cup[2 ; 3]$