How do you simplify #(4+ sqrt8)(4- sqrt8)#? Algebra Radicals and Geometry Connections Multiplication and Division of Radicals 1 Answer Deepak G. Aug 22, 2016 #=8# Explanation: #(a+b)(a-b)=a^2-b^2# Similarly #(4+sqrt8)(4-sqrt8)# #=4^2-(sqrt8)^2# #=16-8# #=8# Answer link Related questions How do you simplify #\frac{2}{\sqrt{3}}#? How do you multiply and divide radicals? How do you rationalize the denominator? What is Multiplication and Division of Radicals? How do you simplify #7/(""^3sqrt(5)#? How do you multiply #(sqrt(a) +sqrt(b))(sqrt(a)-sqrt(b))#? How do you rationalize the denominator for #\frac{2x}{\sqrt{5}x}#? Do you always have to rationalize the denominator? How do you simplify #sqrt(5)sqrt(15)#? How do you simplify #(7sqrt(13) + 2sqrt(6))(2sqrt(3)+3sqrt(6))#? See all questions in Multiplication and Division of Radicals Impact of this question 883 views around the world You can reuse this answer Creative Commons License