How do you factor x^2+18x+81x2+18x+81? Algebra Polynomials and Factoring Factoring Completely 1 Answer Shwetank Mauria Jun 1, 2016 x^2+18x+81=(x+9)^2x2+18x+81=(x+9)2 Explanation: As 8181 is the square of 99 and middle term 1818 is double of this number, (compare it with (x+a)^2=x^2+2ax+a^2(x+a)2=x2+2ax+a2) Hence x^2+18x+81x2+18x+81 is a complete square. x^2+18x+81x2+18x+81 = x^2+2xx9xx x+9^2x2+2×9×x+92 = (x+9)^2(x+9)2 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^2-82x2−8? Which method do you use to factor 3x(x-1)+4(x-1) 3x(x−1)+4(x−1)? What are the factors of 12x^3+12x^2+3x12x3+12x2+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^2-7512c2−75 completely? How do you factor x^6-26x^3-27x6−26x3−27? How do you factor 100x^2+180x+81100x2+180x+81? See all questions in Factoring Completely Impact of this question 49981 views around the world You can reuse this answer Creative Commons License