For the function $y=x^3+ x^2 - 42 x$,

its $y$-intercept is $y =$

its $x$-intercepts are $x=$ .
Note: If there is more than one answer enter them separated by commas. If there are none, enter none .

When $x\to \infty$, $y \to$ $\infty$ ( Input + or - for the answer )

When $x\to -\infty$, $y \to$ $\infty$ ( Input + or - for the answer )

Your overall score for this problem is