#### Answer

$x^2+8x-20=(x+10)(x-2)$

#### Work Step by Step

The leading coefficient is 1.
Thus, to factor the trinomial, just look for factors of $-20$ whose sum is equal to the coefficient of the middle term.
Note that
$-20=10(-2) \text{ and } 10+(-2)=8$.
Therefore, the factored form of the trinomial is
$(x+10)(x-2)$.