Find the limits (that is, end behaviors) below. Enter INFINITY and -INFINITY for $\infty$ and $-\infty$, respectively.

(a) As $x \to \infty$, $\ \ \displaystyle \frac{-6 x(x^2+9)}{3 + 3 x^{3}} \to$ help (limits)

(b) As $x\to -\infty$, $\ \ \displaystyle \frac{4 x(x + 2)(x-2)}{-2 + 4 x^{4}} \to$ help (limits)