Factor because if we have yz=0 then we can assume y and/or z=0
so factor so the easiest way is to find what 2 numbers add to -6 and multiply to get 9 so we know that they must be both - because we must have x+x=(-) and x^2=+ so therefor they must be negative factors of 9=3 and 3 so -3 and -3 -3+-3=-6 perfect
