SOLUTION: Please help me. perform the indicated operation. write the result in the form a + bi. (5i)(-4i)

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Question 453281: Please help me. perform the indicated operation. write the result in the form
a + bi. (5i)(-4i)
Answer by CubeyThePenguin(3113) About Me  (Show Source):
You can put this solution on YOUR website!
Remember that i^2 = -1.

(5i)(-4i)
= -20i^2
= 20