# What is the complex conjugate of -2 +5i ?

$- 2 - 5 i$
For any complex number $z \in \mathbb{C}$, written in rectangular form as $x = x + i y$, then the complex conjugate is given by $\overline{z} = x - i y$.
Note that $z \overline{z} = {x}^{2} + {y}^{2} \in \mathbb{R}$