I am stuck again! I can't factorise this to find stationary points!
y= x^3 + x^2 - 4x - 4
y'= 3x^2 +2x-4

how to factorize??

I assume you want to factor 3x^{2}+2x-4?

It does not factor. That is why you are having a rough time.

Use the quadratic formula.

To tell rather or not a quadratic will factor or not, check the discriminant. b^{2}-4ac

If it is a perfect square, then it will factor. We have 2^{2}-4(3)(-4)=52

52 is not a perfect square so it is not factorable.

You can however find the stationary points using the formula that galactus said. He didn't say it directly, but you should already know it:

x = \frac{-b \pm \sqrt{b^2-4ac}}{2a}

You'll have two values, where the stationary points are found.

yeah I did that. It's all good now. Thanks ^_^