Answer:
x-3
Explanation:
first off, you've got to factor this expression
x^2-x-6= (x+2)(x-3)
so that is your expression.
then, you can take a look at the options.
x+2 is a binomial, and x-3 is a binomial
the only option out of those two that is on the screen is x-3.
the answer is x-3
hope this helped!!!