Let $$f(x) = \frac{x^2 + 3 x - 4}{3x^2 + 11 x - 4}.$$ Find the horizontal and vertical asymptotes of $f(x)$. If there are no asymptotes of a given type, enter 'none'. If there are more than one of a given type, list them separated by commas.

Horizontal asymptote(s): $y$ =

Vertical asymptote(s): $x$ =