Question

RESOLVA: a) (1+2i).(2+4i) b) (2-3i).(5+6i)

Answer 1

a)(1+2i).(2+4i)

$2 + 4i + 4i + 8 {i}^{2} \\ 2 + 8i + 8( - 1) \\ 2 + 4i - 8 \\ 4i - 6$

b)(2-3i). (5+6i)

$10 + 8i - 15i - 18 {i}^{2} \\ 10 - 7i - 18( - 1) \\ 10 - 7i + 18 \\ - 7i + 28$

Espero ter ajudado