Factor \(-x^3+2x+18\text{.}\)

There are no common factors in those three terms, and it would be correct to state that this polynomial is prime or irreducible. However, since its leading coefficient is negative, it may be wise to factor out a negative sign. So, it could be factored as \(-\mathopen{}\left(x^3-2x-18\right)\mathclose{}\text{.}\) Note that every term is negated as the leading negative sign is extracted.