# What are the factors of $$x^{2}-x-12$$?

(B) (x-4)(x+3)

Explanation

Factoring of trinomials is usually done using the reverse foil method, if you are familiar with it. A simple explanation of the method would be:
Write a general format:
(x + _)(x + _)
Think of two numbers to plug into the blank spaces which when multiplied will give you -12, but when added will give you -1. This will need quite a lot of practice, but you will get used to it.The two numbers are obviously -4 and 3.
When multiplied: (-4)(3) = -12
When added: -4 + 3 = -1
The correct factors, then, are:
(x – 4)(x + 3)