Dominant 7th chords and their derivitives use the mixolydian mode exclusively. We are only going to be dealing with un-altered dominant 7th chords in this tutorial. Any dominant 7th chords with altered extensions (b5, #5, b9, #9, #11) will be dealt with in another tutorial.
Here's the list of chords which utilize the mixolydian mode.
Chord | Scale |
7 | Mixolydian |
9 | Mixolydian |
13 | Mixolydian |
7sus4 | Mixolydian |
9sus4 | Mixolydian |