Math mod 2

Anyone know how to do that question where it was like x+2b is a factor and you had to pick an equation? The answer choices were 3x2 +9x +18b, 3x2 +24x +18b, 3x2+30x+18b and 3x2 +39x+18b, anyone know how to do it? I guessed 3x2 +39x+18b