How do you factor the trinomial #x^2-3x-18#?
We have a trinomial with a one in front of
The general formula for a quadratic equation is
You can check that this is correct by the distributive property, and you should find that it matches the original equation.
Sometimes, this type of factoring will be given in terms of real life situations. In that case, you will most likely reject the negative factor, and only use the positive factor. But for this type of question, both factors can work.
Be sure to plug in your factors into the original equation to check your work.