First, I see

, so I know the first factors must be

, and I see the last is a negative, so I know the signs are different

but what comes next? Do I have to try every combination of factors, and use FOIL until I find the correct combination? This is possible when I am working with these small numbers, because 12 only has a few factors (1*12,2*6,3*4), but what if it is made of larger numbers which could have dozens of different factors? It could take a whole day to finish a single problem.

This one is even more difficult, I also have to find the correct factors of 4

Aren't there any tricks to make this more simple?