Question

Efetue:
b) (3+4i).(2-6i)
c) (1+i).(8+2i)
d) (5+i).(5-i)

Answer 1

Resposta:

efetue:

b) (3+4i).(2-6i)

c) (1+i).(8+2i)

d) (5+i).(5-i)

Explicação passo-a-passo:

:-[:-*;-):-*(+_+):-$:-*(*_*):-$:-((*_*):‑X;-):-((*_*)

Answer 2

b) (3+4i).(2-6i) =

6 - 18i + 8i - 24i² =

6 - 10i - 24i² =

- 24i² - 10i + 6 = ÷ ( - 2 )

12i² + 5i - 3 = 0

DELTA = b² - 4.a.c

DELTA = 5² - 4 . (12). (-3)

DELTA = 25 + 144

DELTA = 169

i = - b +/- raiz quadrada de 169 / 2 × 12

i = - ( +5) +/- 13 / 24

i1 = - 5 - 13 / 24

i1 = - 18 / 24

i1 = - 0, 75

i2 = - 5 + 13 / 24

i2 = 8 / 24

i2 = 0, 33

S = { - 0, 75 , 0, 33 }

c) (1+i).(8+2i) =

8 + 2i + 8i + 2i² =

2i² + 10i + 8 = ÷ ( 2)

i² + 5i + 4 = 0

DELTA = b² - 4.a.c

DELTA = 5² - 4 . (1). (4)

DELTA = 25 - 16

DELTA = 9

$i \: = \frac{ - b \: + - \sqrt{9} }{2a}$

$i = \frac{ - ( + 5) + - 3}{2}$

$i1 = \frac{ - 5 - 3}{2}$

$i1 = \frac{ - 8}{2}$

i1 = - 4

$i2 = \frac{ - 5 + 3}{2}$

$i2 = \frac{ - 2}{2}$

i2 = - 1

S = { - 4, - 1 }

d) (5+i).(5-i) =

25 - 5i + 5i - i² =

- i² + 25 = × ( - 1 )

i² - 25 = 0

i² = 25

$i \: = \sqrt{25}$

i = 5