How do you simplify #-8i-7i#? Precalculus Complex Numbers in Trigonometric Form Complex Number Plane 1 Answer Alan P. Feb 18, 2017 #-8i-7i=color(green)(-15i)# Explanation: Here is an image of how #color(red)(-8i)# and #color(blue)(-7i)# would combine in the Complex plane: Answer link Related questions What is the complex number plane? Which vectors define the complex number plane? What is the modulus of a complex number? How do I graph the complex number #3+4i# in the complex plane? How do I graph the complex number #2-3i# in the complex plane? How do I graph the complex number #-4+2i# in the complex plane? How do I graph the number 3 in the complex number plane? How do I graph the number #4i# in the complex number plane? How do I use graphing in the complex plane to add #2+4i# and #5+3i#? How do I use graphing in the complex plane to subtract #3+4i# from #-2+2i#? See all questions in Complex Number Plane Impact of this question 1472 views around the world You can reuse this answer Creative Commons License