Work Step by Step
The leading coefficient is 1 so the trinomial can be factored by looking for the factors of the third term whose sum is equal to the coefficient of the middle term. Note that $-18 = -6(3)$ and $-6 + 3 = -3$. Thus, the factors of the the trinomial are $x-6$ and $x+3$. Therefore, $x^2-3x-18=(x-6)(x+3)$.