How do you factor #x²-10x+21#? Algebra Polynomials and Factoring Factoring Completely 1 Answer Meave60 Nov 18, 2015 #x^2-10x+21=(x-3)(x-7)# Explanation: #x^2-10x+21# Find two numbers that when added equal #-10#, and when multiplied equal #21#. The numbers #-3# and #-7# meet the criteria. #x^2-10x+21=(x-3)(x-7)# 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 #2x^2-8#? Which method do you use to factor #3x(x-1)+4(x-1) #? What are the factors of #12x^3+12x^2+3x#? How do you find the two numbers by using the factoring method, if one number is seven more than... How do you factor #12c^2-75# completely? How do you factor #x^6-26x^3-27#? How do you factor #100x^2+180x+81#? See all questions in Factoring Completely Impact of this question 40712 views around the world You can reuse this answer Creative Commons License