The dominant seventh chord (more commonly called seventh chord) is created by adding the flattened seventh note of the major scale to the major chord.
For example, The Bb7 chord is based upon the notes of the Bb major scale.
Be careful not to confuse the chord formulas for the maj7 and dominant 7th chords.
Example 51 incorporates the dominant seventh chords as outlined on the previous page.
Example 52 uses the Bb dominant seventh arpeggio over two octaves ascending and descending.