Question

Resolução de (14 + 7i)²?

Answer 1

$(14+7i)^2=\\\\\left[7(2+i)\right]^2=\\\\49(2^2+2\cdot2\cdot\,i+i^2)=\\\\49(4+4i-1)=\\\\\boxed{49(3+4i)}$

A saber,

$(a+b)^2=(a)^2+2\cdot(a)\cdot(b)+(b)^2$