Precalculus: Mathematics for Calculus, 7th Edition

$z=a+bi$ Therefore $z=\frac{}{.}(\frac{}{z})=a+bi$
$z=a+bi$ Find the conjugate of the complex number by changing the sign of their imaginary part: $\frac{}{z}=a-bi$ So $\frac{}{.}(\frac{}{z})=a+bi$ Therefore $z=\frac{}{.}(\frac{}{z})=a+bi$