Question

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

Answer 1

the complex conjugate is: `7+3i`
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+ib` becomes `barz=a-ib` .

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:
`(7-3i)*(7+3i)=`

(Remembering that: `i^2=-1`)