Answer
$-3$
Work Step by Step
Recall that if $ f $ is a polynomial function, then we have $\lim_\limits{x\to a}f(x)=f(a)$.
In order to to find the limit, we will plug $ a $ into the function and then simplify.
$\lim_\limits{x\to 2} \dfrac{3x}{x-4}=\dfrac{\lim_\limits{x\to 2} 3 x}{\lim_\limits{x\to 2} (x-4)}=\dfrac{6}{(-2)}=-3$
