Question

Resolva:

a) x2 + 36 = 0
b) x2 + 49 = 0

9) Resolva (7 - 2i).(-4 + 8i)​

Answer 1

Resposta:

Olá!

Explicação passo-a-passo:

a) $x^2+36=0$

$x^2=-36$

$x=\sqrt{-36}$

$x=\sqrt{-1}*\sqrt{36}$

$x=i*6$

$x=6i$

b) $x^2+49=0$

$x^2=-49$

$x=\sqrt{-49}$

$x=\sqrt{-1}*\sqrt{49}$

$x=\sqrt{-1}*\sqrt{49}$

$x=i*7$

$x=7i$

9. $(7-2i)*(-4+8i)$

$(7*-4)+(7*8i)+(-2i*-4)+(-2i*8i)$

$-28+56i+8i-16i^2$  => $i^2=-1$

$-28+56i+8i-16.(-1)$

$-28+56i+8i+16$

$-28+16+56i+8i$

$-12+64i$

Bons Estudos!