How do you solve #x^2 + 8x + 16 = 9#? Algebra Quadratic Equations and Functions Comparing Methods for Solving Quadratics 1 Answer Suren Abreu Feb 27, 2017 #x=-1# or #x=-7# Explanation: #x^2+8x+16=9# Subtract #9# from both sides. #x^2+8x+7=0# Factorise. #x^2+7x+x+7=0# #x(x+7)+1(x+7)=0# #(x+1)(x+7)=0# #x+1=0# and #x+7=0# #x=-1# and #x=-7# Answer link Related questions What are the different methods for solving quadratic equations? What would be the best method to solve #-3x^2+12x+1=0#? How do you solve #-4x^2+4x=9#? What are the two numbers if the product of two consecutive integers is 72? Which method do you use to solve the quadratic equation #81x^2+1=0#? How do you solve #-4x^2+4000x=0#? How do you solve for x in #x^2-6x+4=0#? How do you solve #x^2-6x-16=0# by factoring? How do you solve by factoring and using the principle of zero products #x^2 + 7x + 6 = 0#? How do you solve #x^2=2x#? See all questions in Comparing Methods for Solving Quadratics Impact of this question 2865 views around the world You can reuse this answer Creative Commons License