## Precalculus (6th Edition) Blitzer

$-1(x+5)(x-1)$
Factor out $-1$ to obtain: $=-1(x^2+4x-5)$ The leading coefficient of the trinomial is $1$. This means that the trinomial can be factored by looking for the factors of the constant term $(-5)$ whose sum is equal to the coefficient of the middle term. $(4)$. Note that: $-5 = 5(-1)$ and $5+(-1) = 4$ Thus, the factors we are looking for are $5$ and $-1$. This means that the factors of the trinomial are $x+5$ and $x-1$. Therefore, the completely factored form of the given polynomial is: $=-1(x+5)(x-1)$