How do you factor completely #81 x^4 - 256#? Algebra Polynomials and Factoring Factoring Completely 1 Answer 冠廷 李. Aug 8, 2016 #(9x^2+16)(3x+4)(3x-4)# Explanation: #3^4x^4-16^2# =#(3x)^4-16^2# =#(9x^2)^2-16x^2# =#(9x^2+16)(9x^2-16)# =#(9x^2+16)(3x+4)(3x-4)# 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 1252 views around the world You can reuse this answer Creative Commons License