with the box you have four squares the first square holds the first term and the last square holds the last term. ex problem 2x^2-x-1
_x__ _-1_
2x | 2x^2 -2 x | multiply those numbers together
1| 1x_-1_| -2 so you want to look at the common factors that equal to -x -2 and 1 do it the take out the commons between those 1+2x and x-1