ANSWER
[tex]( - \infty , - 7) \cup( - 7 , 0) \cup(0 , 7 )\cup(7 , + \infty )[/tex]
EXPLANATION
The given function is
[tex]h(x) = \frac{9x}{x( {x}^{2} - 49) } [/tex]
This function is defined for values where the denominator is not equal to zero.
[tex]x( {x}^{2} - 49) \ne0[/tex]
[tex]x(x - 7)(x + 7) = 0[/tex]
The domain is
[tex] x \ne - 7, x \ne0, \: and \: x \ne 7,[/tex]
Or
[tex]( - \infty , - 7) \cup( - 7 , 0) \cup(0 , 7 )\cup(7 , + \infty )[/tex]
