Question

3.Calcule : (2 – 5i)² Ajudem por favor

Answer 1

Explicação passo-a-passo:

$\sf (2-5i)^2=2^2-2\cdot2\cdot5i+(5i)^2$

$\sf (2-5i)^2=4-20i+25i^2$

$\sf (2-5i)^2=4-20i+25\cdot(-1)$

$\sf (2-5i)^2=4-20i-25$

$\sf (2-5i)^2=-21-20i$