# What is complex conjugate of -5-7i?

$- 5 + 7 i$
The complex conjugate of the complex number $a + b i$ is $a - b i$.
In other words, switch the sign (from positive to negative, or vice versa) of the term with the $i$.
Thus, the complex conjugate of $- 5 \textcolor{red}{-} 7 i$ is $- 5 \textcolor{red}{+} 7 i$.