How do you factor #3a^3b + 21a^2b^4#? Algebra Polynomials and Factoring Factoring Completely 1 Answer Typo Jun 26, 2018 #3a^2b(a+7b^3)# Explanation: #3a^3b+21a^2b^4# #=3(a^3b+7a^2b^4)# #=3a^2(ab+7b^4)# #=3a^2b(a+7b^3)# 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 1759 views around the world You can reuse this answer Creative Commons License