How do you simplify #3sqrt5 * sqrt5#? Algebra Radicals and Geometry Connections Multiplication and Division of Radicals 1 Answer mason m Jun 3, 2016 #15# Explanation: Don't be confused by what #3sqrt5# means. It is just the multiplication of #3# and #sqrt5#, so #3sqrt5=3*sqrt5#. Therefore #3sqrt5*sqrt5=3*sqrt5*sqrt5#. We see that #sqrt5*sqrt5=5#, so our expression becomes #3sqrt5*sqrt5=3*(sqrt5*sqrt5)=3*5=15#. 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 1094 views around the world You can reuse this answer Creative Commons License