hello
for the first one you should have $\displaystyle 3x-4\neq 0$ which means $\displaystyle x\neq \frac{4}{3}$.
so the domain is $\displaystyle \mathbb{D}= \mathbb{R}\setminus \left \{ \frac{4}{3} \right \}$
for the second one,you have $\displaystyle x^{2}\geq 0\Leftrightarrow x^{2}-9\geq -9\Leftrightarrow \frac{1}{x^{2}-9}\leq -\frac{1}{9}$and so the range is $\displaystyle (-\infty,-\frac{1}{9}]$
(still need confirmation)