Question

Urgente
Efetue:
a) (1+3i)+(-2+i)=
b) (4-i)+(5-2i)=
c) (8-i)-(8-2i)-(8+4i)=
d) (1-i).(1+i)=

Answer 1

$(1+3i)+(-2+i)=1-2+3i+i\\\\ \boxed{(1+3i)+(-2+i)=-1+4i}$

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$(4-i)+(5-2i)=4+5-i-2i\\\\ \boxed{(4-i)+(5-2i)=9-3i}$

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$(8-i)-(8-2i)-(8+4i)=(8-8-i+2i)-(8+4i)\\ (8-i)-(8-2i)-(8+4i)=i-(8+4i)\\ (8-i)-(8-2i)-(8+4i)=-8+i-4i\\\\ \boxed{(8-i)-(8-2i)-(8+4i)=-8-3i}$

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$(1-i)\cdot(1+i)=1\cdot1+1\cdot i-i\cdot1-i\cdot i\\ (1-i)\cdot(1+i)=1+i^2\\ (1-i)\cdot(1+i)=1+(-1)\\ (1-i)\cdot(1+i)=1-1\\\\ \boxed{(1-i)\cdot(1+i)=0}$