What is the negative square root of 27? Algebra Radicals and Geometry Connections Simplification of Radical Expressions 1 Answer George C. Jul 14, 2015 The negative square root of #27# is #-sqrt(27) = -3sqrt(3)# Explanation: #x^2=27# has two solutions, which we call #+-sqrt(27)# #sqrt(27)# denotes the positive square root. #-sqrt(27)# is also a square root of #27#, which we call the negative square root of #27# If #a, b >= 0# then #sqrt(ab) = sqrt(a)sqrt(b)#. So: #-sqrt(27) = -sqrt(3^2*3)=-sqrt(3^2)sqrt(3) = -3sqrt(3)# Answer link Related questions How do you simplify radical expressions? How do you simplify radical expressions with fractions? How do you simplify radical expressions with variables? What are radical expressions? How do you simplify #root{3}{-125}#? How do you write # ""^4sqrt(zw)# as a rational exponent? How do you simplify # ""^5sqrt(96)# How do you write # ""^9sqrt(y^3)# as a rational exponent? How do you simplify #sqrt(75a^12b^3c^5)#? How do you simplify #sqrt(50)-sqrt(2)#? See all questions in Simplification of Radical Expressions Impact of this question 6987 views around the world You can reuse this answer Creative Commons License