[tex](f\cdot g)(x)=f(x)\cdot g(x)\\\\\text{We have}\ f(x)=x+7\ \text{and}\ g(x)=\dfrac{1}{x-13}.\\\\\text{Substitute}\\\\(f\cdot g)(x)=(x+7)\cdot\dfrac{1}{x-13}=\dfrac{x+7}{x-13}\\\\\text{The domain:}\\\\x-13\neq0\qquad\text{add 13 to both sides}\\\\x\neq13\\\\Answer:\ \boxed{x\in\mathbb{R}-\{13\}}\to\boxed{\text{All real numbers except 13}}[/tex]
