here is link which may help you
Factor theorem - Wikipedia, the free encyclopedia
Hi Maditay,
That first one doesn't make a lot of sense. Turns out to be x = 809. What's to factor? It's linear.
The last one can be grouped to factor. Bring everything to the left side and set equal to zero.
Finish up by factoring out the common factor of (x - 3), and then use your zero product property.