SOLUTION: (4 - i)(4 + i) i had 16 + 4i -4i - 0 but i think im doing this completely wrong . I would provide you with the book, but my class does not learn off of books therefore I do

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: (4 - i)(4 + i) i had 16 + 4i -4i - 0 but i think im doing this completely wrong . I would provide you with the book, but my class does not learn off of books therefore I do       Log On


   

Question 190277: (4 - i)(4 + i)
i had 16 + 4i -4i - 0
but i think im doing this completely wrong . I would provide you with the book, but my class does not learn off of books therefore I do not have one.
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
%284+-+i%29%2A%284+%2B+i%29 Start with the given expression.


%284%29%284%29%2B%284%29%28i%29%2B%28-i%29%284%29%2B%28-i%29%28i%29 FOIL.


16%2B4i-4i-i%5E2 Multiply.


16%2B4i-4i-1%28-1%29 Replace i%5E2 with -1. Note: i%5E2=-1.


16%2B4i-4i%2B1 Multiply.


17 Combine like terms.


So %284+-+i%29%2A%284+%2B+i%29=17.