Answer:
I – IV – V in every key: C major: C-F-G. D♭ major: D♭-G♭-A♭ ...
I – V – vi – IV in every key: C major: C-G-Am-F. D♭ major: D♭-A♭-B♭m-G♭ ...
ii – V – I in every key: C major: Dm-G-C. D♭ major: E♭m-A♭-D♭ ...
I – V – vi – iii – IV – I – IV – V in every key: C major: C-G-Am-Em-F-C-F-G.
Explanation: