Question

efetue ... alguem me ajuda por favor

Answer 1

Lembrando que i²= -1  

a) (5 + 3i) . (2+ 4i)  

5.2 + 5.4i + 3i.2 + 3i.4i

10 + 20i + 6i +12i²  

10 + 20i + 6i + 12. (-1)  

10 + (20 + 6) i - 12

(10 - 12) + (20 +6)i

-2 + 26i  

b) (3 – 2i) . (4+ 5i)  

3.4 + 3.5i – 2i.4 -2i.5i

12 + 15i – 8i – 10i²

12 + 7i – 10 . (-1)  

12 + 7i +10

22 + 7i  

c) (-4-4i). (2-3i)

-4.2 + (-4. -3i) – 4i.2 + (-4i.-3i)

-8 + 12i – 8i + 12i²

-8 + 4i + 12. (-1)

-8+ 4i – 12  

-20 + 4i

(-20+4i) . (-1)

20 – 4i

d) (8+3i). (8-3i)

8.8 + (8. -3i) + 3i.8 + (3i. -3i)

64 – 24i + 24i -9i²

64 -9i²

64 – 9. (-1)

64 + 9  

73

e) (-8i).(-8i)

64i²

64. (-1)

-64