Watch the I bVII IV I Progression in C online guitar lesson by Brad Carlton from Guitar Lab: Vertical Soloing

This lesson lays out the C Bb F C progression in 8th position. The C chord is played with the E form, the Bb uses the D form, and the F uses the A form. The major pentatonics are 4th string root for the C, 2nd string root for the Bb, and 3rd string root for the F. The parent scale (theoretical key) is F major and all three of these major pentatonic scales would exist as subsets of scale form IV of the F major scale.