## Calculus (3rd Edition)

$R- \{-4,0,3\}$.
We see that $x^{-1}=\frac{1}{x}$ is not defined at $x=0$. Also $(x-3)(x+4)=0$ at $x=3$ or $x=-4$. Hence, the domain of $f$ is $R- \{-4,0,3\}$ (all real numbers except $-4$, $0$, and $3$).