Question

Efetue: (4+i).(2-i)+3-i

Answer 1

Lembre-se de que $i^{2}=-1$

$(4+i).(2-i)+3-i$
$8-4i+2i-i^{2}+3-i$
$8-4i+2i-(-1)+3-i$
$8-4i+2i+1+3-i$
$8-2i+1+3-i$
$8+1+3-2i-i$
$12-3i$