\[\frac{x - 2}{x^{2} + 6x + 9} \Longrightarrow x^{2} + 6x + 9 \neq 0,\ \]
\[(x + 3)^{2} \neq 0,\ \]
\[x + 3 \neq 0 \Longrightarrow x \neq - 3.\]
\[при\ любом\ x \neq - 3.\]