Eb Major
The dominant note is the 5th note in the scale. In the B Major scale, F is the dominant note.
The subdominant in a scale is the 4th, which in the key of B-flat major is E-flat.
b flat, c, d, e flat, f, g, a, b flat
G-flat major scale has the most with 6 flats: b-flat, e-flat, a-flat, d-flat, g-flat, and c-flat.Of course, one could argue that other scales have more flats (such as C-flat major, F-flat major, B-double-flat major, etc), but these scales are typically notated as their enharmonic equivalent (e.g. A major instead of B-double-flat major).
The major scale with three flats is the E-flat major scale. The key signature for E-flat major consists of three flats: B-flat, E-flat, and A-flat, arranged from left to right on the staff. The scale ascending from the first degree (E-flat) is E-flat, F, G, A-flat, B-flat, C, D, and returns to E-flat.
The dominant note is the 5th note in the scale. In the B Major scale, F is the dominant note.
The subdominant in a scale is the 4th, which in the key of B-flat major is E-flat.
The dominant is the 5th tone in the scale. In a D Major scale, the dominant is A.
The dominant of B is F#.
The mediant of B flat major is D.
The dominant of B is F#.
B-flat
Eb Major
The dominant is the 5th, which in the key of A-flat major is E-flat. Then an E-flat major triad contains the notes E-flat, G, and B-flat.
The B-flat major scale contains two flats: B-flat and E-flat. However, if you're looking for a scale that has only one B-flat, it would be the G minor scale, which is the relative minor of B-flat major. In G minor, the B-flat appears as the sixth scale degree, while the scale itself includes B-flat as part of its harmonic and melodic variations.
A-flat Major scale
The tonic of E flat major is E flat. Its dominant is B flat and its subdominant is A flat.