Question

12 - Determine o valor de (5 - i).(3 - 2i): *

Answer 1

Determinar o valor :

$\sf = (5 - i) \cdot (3 - 2i)$

$\sf = 5\cdot3 + 5\cdot(-2i) + (-i)\cdot3 + (-i)\cdot(-2i)$

$\sf = 15 - 10i - 3i + 2i^2$ => i² = (-1)

$\sf = 15 - 13i + 2\cdot(-1)$

$\sf = 15 - 13i - 2$

$\boxed{\sf = 13 - 13i}$