How do you factor 21 - 4x - x^2? Algebra Polynomials and Factoring Factorization of Quadratic Expressions 2 Answers Mark D. May 21, 2018 (7+x)(3-x) Answer link smendyka May 21, 2018 21 - 4x - x^2 = (7 + x)(3 - x) Answer link Related questions How do you factor trinomials? What is factorization of quadratic expressions? How do you factor quadratic equations with a coefficient? What are some examples of factoring quadratic expressions? How do you check that you factored a quadratic correctly? How do you factor x^2+16x+48? How do you factor x^2-9x+20? Question #3fdac How do you factor 8+z^6? There is no GCF to be factor out, so is there another method to complete this? How do you factor 2t^2+7t+3? See all questions in Factorization of Quadratic Expressions Impact of this question 1743 views around the world You can reuse this answer Creative Commons License