Pentatonic and Blues Scales can be found two ways 1-The Hard Way By using the Major Scales and Modes Slide Rule and plotting out the formulas shown, or 2-The Easy Way By using the Blues and Pentatonic Slide Rule and following the numbers 1.2.B.3.5.6. The 6th note of any Major Scale is known as the relative minor e.g. in the Key of: C Major. A minor is the relative minor. C being the first note and A being the sixth note of the C Major Scale in the Key of: G Major. E minor is the relative minor. G being the first note and E being the sixth note of the G Major Scale So the Easy Way to find any Major Pentatonic Scale is slide insert so the No. 1 is over the Key you want Wherever the sixth note is will also be the Minor Pentatonic. See the Diagram 1 below.
Diagram 1 The Easy Way using Pentatonic slide rule The G Major Pentatonic Scale here is the same as the E minor Pentatonic Scale No.1 is the Tonic G (G)=G Major Pentatonic No.6 is the Relative Minor E (E)=E Minor Pentatonic
Diagram 2 The Hard Way using Major Scale slide rule The Diagram here shows the G Minor Pentatonic Scale Plotted out using the Major Scale Slide Rule Notice this is the same as the Bb Major Pentatonic Scale But this can be a very confusing Way to find the Pentatonic and or Blues Scales
In brief, the Easy Way is: 1-Use the Pentatonic Slide Rule 2-To find any Major Pentatonic Scale slide insert so the No. 1 is over the Key you want 3-To find any Minor Pentatonic Scale slide insert so the No. 6 is over the Key you want. Easy
If you want to practice your soloing using the blues and pentatonic scales follow this Link The Jam-Room Here you will find video files of Blues chord Progressions in different Keys plus links to other on line resources of mine