Question

z1=2+3i  e z2 =1-4i    z1 . z2 é

Answer 1

(2 + 3i)(1 - 4i)
2 -8i + 3i -12i^2
2 -5i + 12
14 - 5i

z1 . z2 = 14 - 5i

Answer 2

$Z_{1} .Z_{2} =(2+3i).(1-4i)\\\\Z_{1} .Z_{2} =2-8i+3i-12i^2\\\\Z_{1} .Z_{2} =2-5i-12(-1)\\\\Z_{1} .Z_{2} =2-5i+12\\\\\boxed{Z_{1} .Z_{2} =14-5i}$

Beleza..Barbara..