Question 1007611: i am having trouble with my complex numbers homework. the problem is -7(-4i)(-5-3i) could you explain it to me ? Answer by Alan3354(69443) (Show Source):
You can put this solution on YOUR website! i am having trouble with my complex numbers homework. the problem is -7(-4i)(-5-3i) could you explain it to me ?
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-7(-4i)(-5-3i)
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Step 1, say what you want to do.
If you want to multiply that:
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-7(-4i)(-5-3i)
-7*(-4i) = 28i
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--> 28i*(-5-3i)
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= -140i - 84i^2
i^2 = -1
--> -140i + 84
= 84 - 140i
