Question

3- Faça as multiplicações de números complexo.
a) (15 + 3i) (2 +4i)
b) (7 - 2i) (4 + 5i)
c) (6-4) (2-3i)
d) (16 + 3i) (8 -3i)
e) (-81) (-8i)
f) (7 - 2i) (5 - 21)
g) (13-i) (-1 + i)
h) (9-i) (7-i)
i) (-12) (-3i)
j) (9- 2i) (-1 + 2i)9​

Answer 1

Resposta:

a) (15 + 3i) (2 +4i) =30+60i +6i -12=18+66i

b) (7 - 2i) (4 + 5i) =28 +35i-8i +10 =38+27i

c) (6-4) (2-3i) =4-6i

d) (16 + 3i) (8 -3i) =128 -48i+24i +9 =137-24i

e) (-81) (-8i) =648i

f) (7 - 2i) (5 - 21) = 35 -147-10i +42i  =-112+32i

g) (13-i) (-1 + i) =-13+13i +i+1 =-12+14i

h) (9-i) (7-i) =63-9i -7i +1 =64 -16i

i) (-12) (-3i) =36i

j) (9- 2i) (-1 + 2i)⁹ =(9-2i)*(-1+2i) * (-1+2i)⁸

=(-9+18i+2i+4)*(-1+2i)⁸

=(-5+20i) *(-1+2i)⁸

=(-5+20i) *[(-1+2i)²]⁴

(-5+20i) *[1-4i-4]⁴

(-5+20i) *[-4i-3]⁴

(-5+20i) *[(4i+3)²]²

(-5+20i) *[-16 +24i+9]²

(-5+20i) *[-7 +24i]²

(-5+20i) *[49 -336i-576]

(-5+20i) *[ -336i-527]

5*336i +5*527 +20*336-20*557i

=9355 -9460i