Suppose $f(x) = x^{2}\!\left(7-8x^{9}\right)$.

(a) The roots of $f(x)$ are $x =$ help (numbers) (If a root is repeated, enter it only once.)

(b) As $x \to \infty$, $f(x) \to$ help (numbers)

(b) As $x \to -\infty$, $f(x) \to$ help (numbers)