so for the first one it is (x-3)(x+3) this is because it is a difference of squares so you square root the 9 and the minus you do both +and - in order to keep up the -9
The zeros are:x=3 and x=-3 ( this is because you change the sign in the bracket
the others should be pretty simple to do for number 2 its a complex
the third is a simple trinomial
and fourth is simple trinomial as well