How do you simplify #(-5-4i)(3-7i)#?

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Answer 1 · 2016-06-23T16:07:27

#-43 +23i#

To simplify #(-5-4i)(3-7i)#

Begin by using FOIL (First Outers Inners Lasts) to distribute and multiply the binomials.

#-(5)(3) -(5)(-7i) -(4i)(3)-(4i)(-7i)#

#-15 +35i -12i+28i^2#

In Euler's notation #i^2=-1#

#-15 +35i -12i+28(-1)#

#-15 +35i -12i-28#

Combine like terms

#-43 +23i#