Resposta :

3478elc
a) (2+i)2 = 4 + 4i + i^2 ==> 4 + 4i - 1 ==> 3 + 4i
- i.(2+i)-(2-1)= -(4-i^2)i ==> -(4+1)i ==> - 5i

b) (1+i)2 =1 + 2i + i^2 ==> 1 + 2i - 1 ==> 2i
 - (1-i)2 = -(1 - 2i + i^2) ==> -(1 + 2i - 1) ==> - 2i

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