a) $g(x)=\dfrac{4 x^{3}}{x^{3}-1}$

As $x$ goes to $+\infty$, $g(x)$ goes to .
As $x$ goes to $-\infty$, $g(x)$ goes to .
Horizontal asymptote: $y =$

b) $f(x)=\dfrac{3}{(x- 4 )^{6}}$

As $x$ goes to $+\infty$, $f(x)$ goes to .
As $x$ goes to $-\infty$, $f(x)$ goes to .
Horizontal asymptote: $y =$

Hint: