# What is complex conjugate of 5-7i?

$5 + 7 i$
To find a complex conjugate, simply change the sign of the imaginary part (the part with the $i$). This means that it either goes from positive to negative or from negative to positive.
As a general rule, the complex conjugate of $a + b i$ is $a - b i$.
Therefore, the complex conjugate of $5 - 7 i$ is $5 + 7 i$.