How do you factor x3−2x−21? Algebra Polynomials and Factoring Factoring Completely 1 Answer Binayaka C. Aug 30, 2016 (x2+3x+7)(x−3) Explanation: x3−2x−21=x3−3x2+3x2−9x+7x−21=x2(x−3)+3x(x−3)+7(x−3)=(x2+3x+7)(x−3)[Ans] Answer link Related questions What is Factoring Completely? How do you know when you have completely factored a polynomial? Which methods of factoring do you use to factor completely? How do you factor completely 2x2−8? Which method do you use to factor 3x(x−1)+4(x−1)? What are the factors of 12x3+12x2+3x? How do you find the two numbers by using the factoring method, if one number is seven more than... How do you factor 12c2−75 completely? How do you factor x6−26x3−27? How do you factor 100x2+180x+81? See all questions in Factoring Completely Impact of this question 4643 views around the world You can reuse this answer Creative Commons License