Two nonzero complex numbers such that $| z_1 + z_2 |$ = $| z_1 - z_2 |$. If $z_2 ≠ 0$, show that $\frac{z_1}{z_2}$ is a pure imaginary.
$|z_{1} + z_{2}| = |z_{1} - z_{2}| \implies z_{1}/z_{2}$ is Imaginary