SOLUTION: 2i(4+5i)(4-5i) ___________ __ 4+i

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Question 698041: 2i(4+5i)(4-5i)
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4+i
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
%28%282i%284%2B5i%29%284-5i%29%29%29%2F%284%2Bi%29
FOIL
%28%282i%2816-25%28i%5E2%29%29%29%29%2F%284%2Bi%29 = %28%282i%2841%29%29%29%2F%284%2Bi%29 = %2882i%29%2F%284%2Bi%29
Rationalize the denominator
%2882i%29%2F%284%2Bi%29 * %284-i%29%2F%284-i%29 = %2882i%284-i%29%29%2F%2816-%28i%5E2%29%29 = %28328i-82%28i%5E2%29%29%2F%2816-%28-1%29%29 = %28328i-82%28-1%29%29%2F%2817%29 = %2882%2B328i%29%2F%2817%29