## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

The domain of $R(x)$ is the set of all real numbers $x$ except $-3$. In set notation: $\text{Domain:} \{x|x \neq -3\}$
Rational functions are of the form $$R(x)=\dfrac{p(x)}{q(x)}$$ The domain of the rational function is the set of all real numbers except those for which the denominator $q(x)$ is $0$. $\text{Set the denominator equal to zero}$ then solve to obtain: $$3+x = 0\\[3mm] x=-3$$ The domain of $R(x)$ is the set of all real numbers $x$ except $-3$. $\text{Domain:} \{x|x \neq -3\}$