Answer
$(x+3)(x-3)(x+2)$
Work Step by Step
$x^{3}+2x^{2}-9x-18$
Group terms with common factors.
$(x^{3}+2x^{2})+(-9x-18)$
Factor out the greatest common factor from the grouped terms.
$=x^{2}(x+2)-9(x+2)$
Factor out the common binomial factor $(x+2)$
$=(x^{2}-9)(x+2)$
$(x^{2}-9)$ is a difference of two squares and can be factored.
Using the formula $[(a^{2}-b^{2}) = (a+b)(a-b)]$
$= (x+3)(x-3)(x+2)$
