Take out - 1 k(x) = -1(x^2 - 2x - 15) Now factor what's inside the brackets. The numbers you pick must add to - 2 and multiply to -15. When you multiply to -15 you should note that one of the numbers is plus and the other is minus. (x - )(x + ) is the way it looks. They differ by 2 and the "largest" one is minus. That means your answer is -5 and +3 k(x) = - (x - 5)(x + 3) Now for the zeros. x - 5 can be a zero x - 5 = 0 x = 5