SOLUTION: Hello. I found the division of complex numbers in my book but can't find the multiplication unit in my book. Here is the problem I am trying to work on: Needs to be put in " a+bi "

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: Hello. I found the division of complex numbers in my book but can't find the multiplication unit in my book. Here is the problem I am trying to work on: Needs to be put in " a+bi "      Log On


   



Question 32209: Hello. I found the division of complex numbers in my book but can't find the multiplication unit in my book. Here is the problem I am trying to work on: Needs to be put in " a+bi " form.
+%284%2Bi%29%5E2+. Any help would be greatly appretiated.
Respectfully,
Chris

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
To multiply two binomials such as%284%2Bi%29%284%2Bi%29, you can use the FOIL method.
FOIL = First, Outer, Inner, Last. This is the order in which you would multiply the terms in the binomials.
%284%2Bi%29%284%2Bi%29+=+16+%2B+4i+%2B+4i+%2B+i%5E2 Now you can simplify this. Recall that i%5E2+=+-1
16+%2B+8i+%2B+%28-1%29+=+15+%2B+8i