#### Answer

$(x^n-6)(x^n+3)$

#### Work Step by Step

The given expression can be written as:
$\\(x^n)^2-3x^n-18$
The constant term of $-18$ has the factors $-6$ and 3, the sum of which, -3, is equal to the coefficient of the middle term
Thus, the factored form of the given trinomial is:
$\\=(x^n-6)(x^n+3)$