Welcome to MHF!
In the future please post one problem per thread and show all attempted work so we know what you know.
For #1, first factor this.
You should be able to tell that the three zeros of f(x) are 0, 3 and -3. So draw a number line and mark these three points on it. Now the regions inbetween these values will either be positive or negative. Choose a test point to see. Make sense?