$\"\"$

The function is $\"f(x)=\\frac{x+4}{x^2-9}\"$ .

Simplify the expression.

$\"f(x)=\\frac{(x+4)}{(x+3)(x-3)}\"$

The domain of a function is all values of $\"x\"$ , those makes the function mathematically correct.

The denominator of the function should not be zero.

$\"(x+3)(x-3)\\neq$

$\"x+3\\neq$ and $\"x-3\\neq$

$\"x\\neq$ and $\"x\\neq$ .

The domain of the function is set all values of $\"x\"$ except $\"-3\"$ and $\"3\"$ .

The domain of the function is $\"(-\\infty,$ .

$\"\"$

The domain of the function is $\"(-\\infty,$ .