# What is the complex conjugate for the number 7-3i?

##### 1 Answer
Dec 20, 2014

the complex conjugate is: $7 + 3 i$
To find your complex conjugate you simply change sign of the imaginary part (the one with $i$ in it).
So the general complex number: $z = a + i b$ becomes $\overline{z} = a - i b$ .

Graphically:

(Source: Wikipedia)

An interesting thing about complex conjugate pairs is that if you multiply them you get a pure real number (you lost the $i$), try multiplying:
$\left(7 - 3 i\right) \cdot \left(7 + 3 i\right) =$

(Remembering that: ${i}^{2} = - 1$)