How do you multiply #-11i(3+9i)#?

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Answer 1 · 2018-04-20T13:22:41

#-33i+99#

Given: #-11i(3+9i)#

#=-11i*3-11i*9i#

#=-33i-99i^2#

#=-33i-99*-1#

#=-33i+99#

Answer 2 · 2018-04-20T13:32:16

#99 - 33i#

use "distributive law"

#-11i(3 + 9i) -> (-11i xx3) + (-11i xx9i)#

#-33i + (-99 xx i^2)# *TIP) #i^2 = -1#

#-33i + 99#

#:. -11i(3+9i) = 99 - 33i#