\[\boxed{\text{343.}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\left\{ \begin{matrix}
xy = - 1\ \ \ \\
x + 3y = 0 \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ }\left\{ \begin{matrix}
y = - \frac{1}{x} \\
y = - \frac{x}{3} \\
\end{matrix} \right.\ \]
\[y = - \frac{1}{x}\]
| \[y\] |
\[- 1\] |
\[- \frac{1}{2}\] |
\[- 2\] |
\[1\] |
\[\frac{1}{2}\] |
\[2\] |
\[y = - \frac{x}{3}\]

\[Ответ:2\ решения.\]
\[2)\ \left\{ \begin{matrix}
xy = - 1\ \ \ \ \\
x - 3y = 0 \\
\end{matrix} \right.\ \text{\ \ \ \ \ }\left\{ \begin{matrix}
y = - \frac{1}{x} \\
y = \frac{x}{3}\text{\ \ \ \ \ } \\
\end{matrix} \right.\ \ \]
\[y = - \frac{1}{x}\]
| \[y\] |
\[- 1\] |
\[- \frac{1}{2}\] |
\[- 2\] |
\[1\] |
\[\frac{1}{2}\] |
\[2\] |
\[y = \frac{x}{3}\]

\[Ответ:нет\ решений.\]
\[3)\ \left\{ \begin{matrix}
xy = 6\ \ \ \ \ \ \ \ \ \\
3x - 2y = 6 \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ \ \ \ }\]
\[\left\{ \begin{matrix}
y = \frac{6}{x}\text{\ \ \ \ \ \ \ \ \ \ } \\
y = \frac{3x - 6}{2} \\
\end{matrix} \right.\ \ \]
\[y = \frac{6}{x}\]
| \[y\] |
\[6\] |
\[3\] |
\[2\] |
\[- 6\] |
\[- 3\] |
\[- 2\] |
\[y = \frac{3x - 6}{2}\]

\[Ответ:два\ решения.\ \]