(3-5i)(2+9i)+(7+2i)(7-2i)

1 answer:

kondor19780726 [428]3 years ago

7 0

$i^{2} = -1$

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$(3-5i)(2+9i)+(7+2i)(7-2i) = \\ \\ = 6 + 27i - 10i - 45i^{2} + 49 - 14i + 14i - 4i^{2} = \\ \\ =55 + 17i + 45 + 4 = \boxed{104 + 17i}$

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