How do you factor the expression #5x^2+8x-21#? Algebra Polynomials and Factoring Factorization of Quadratic Expressions 1 Answer P dilip_k Mar 12, 2016 #=>(x+3)5x-7)# Explanation: #5xx21=5xx3xx7=15xx7# 15-7=8 #5x^2+8x-21# #=>5x^2+15x-7x-21# #=>5x(x+3)-7(x+3)# #=>(x+3)5x-7)# 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 2886 views around the world You can reuse this answer Creative Commons License