Question

Calcule os números complexos : ( 1 + 2 i) . (1 - 2i)

Answer 1

▶️lembrando:

• $\boxed{\small{_{i^{2}=-1}}}$

▶️ Resolvendo:

• $\small{_{( 1 + 2 i) . (1 - 2i)}}$

• $\small{_{1.1-2i.(1)+2i.(1)+2i.(-2i)}}$

• $\small{_{1 -2i+2i+4}}$

• $\small{_{1+0+4}}$

• $\small{_{1+4}}$

• $\boxed{\small{_{5}}}$

▶️O resultado será igual a 5