How do you simplify #-sqrt(-9) • sqrt4#? Precalculus Complex Numbers in Trigonometric Form Multiplication of Complex Numbers 1 Answer Kalyanam S. Jul 11, 2018 #=> - 6 i# Explanation: #-sqrt(-9) * sqrt 4# #=> - sqrt (9 i^2) * sqrt 4#, as #i^2 = -1# #=> -i sqrt 9 * sqrt 4# #=> -3 i * 2 = -6i# Answer link Related questions How do I multiply complex numbers? How do I multiply complex numbers in polar form? What is the formula for multiplying complex numbers in trigonometric form? How do I use the modulus and argument to square #(1+i)#? What is the geometric interpretation of multiplying two complex numbers? What is the product of #3+2i# and #1+7i#? How do I use DeMoivre's theorem to solve #z^3-1=0#? How do I find the product of two imaginary numbers? How do you simplify #(2+4i)(2-4i)#? How do you multiply #(-2-8i)(6+7i)#? See all questions in Multiplication of Complex Numbers Impact of this question 1648 views around the world You can reuse this answer Creative Commons License