Question

Multiplicaçao de numeros complexos: (5-3i).(1+2i)

Answer 1

Veja:

-3i * 2i = -3 * 2 * i²

-6.i² = 6

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Lembrar que:

i² = -1
(-i)² = -1

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$(5-3i) . (1 + 2i) \\ \\ \\ 5.1 + 3.2i - 3i.1 - 3i . 2i \\ \\ 5 + 10i - 3i +6 \\ \\ 5 + 6 + 10i - 3i \\ \\ =\ \textgreater \ 11 + 7i$