I think I now see what method you are using. Multiply the first coefficient by the last one: (6)(5) = 30Find factors of 30 whose sum is 17 (if the sign was negative we would need the difference being whatever the middle term was). There are lots of factor combinations of 30, but 2 and 15 add to 17. Replace 17x in the middle with 2x and 15x6x^2 +2x +15x +5Group terms so you can get a similar binomial2x(3x + 1) + 5(3x +1)Factor out the common binomial(2x + 5)(3x+1) and you have the correct factors.Thanks. I'll check some other examples too.