you need to find an initial factor. look at the coefficients of the equation and see if either X=1 or X=-1 would sum to 0. Then you can use synthetic division or the old long division by (X-1) approach to get the other 2 factors. These would be (X-4)*(X-3) = 0 which means X=4 and X=3 are also factors. There is a segment on synthetic division but you have to get the initial factor 1st. Hope this helps.