How do you simplify #-10i(4+7i)# and write the complex number in standard form?

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Answer 1 · 2018-08-10T00:08:39

#70 - 40i#

#-10i(4+7i)#

First, we know that standard form is #a + bi#.

Distribute the #-10i#:
#-40i - 70i^2#

We know that #i^2# equals to #-1#, so
#-40i - 70(-1)#

#-40i + 70#

Put it in the form #a + bi#:
#70 - 40i#

Hope this helps!