Factor the trinomial x^2 - 2x - 8

(x+4) (x-2)

(x-8) (x+1)

(x+8) (x-1)

(x-4) (x+2)

Well what two numbers multiply to get - 8 and add to get - 2?

Well, to get - 8, we either have (-1,8), (-2,4), (-4,2), (-8,1)

8-1=7

-2+4=2

2-4=-2

1-8=-7

Thus it should be (-4,2),

This means we should get (X-4) (X+2)