#### Answer

$+16$

#### Work Step by Step

The leading coefficient of the given trinomial is 1.
Thus, it can be factored by looking for the factors of the constant term ($-48$) whose sum is equal to the numerical coefficient of the middle term ($13$).
Note that $-48=-3(16)$ and $-3+16=13$.
Thus, the given trinomial can be factored as $(x-3)(x+16)$.
Therefore, the term of the second factor is $+16$.