The teacher has written an equation of the form on the board, where is a quadratic, but Heather can't read the linear term. She can see that the quadratic term is and that the constant is . She asks her neighbor, Noel, what the linear term is. Noel decides to tease her and just says, ``One of the roots is 4.'' Heather then says, ``Oh, thanks!'' She then correctly writes down the linear term. What was the linear term?