Key of ?????

What key is C Em7 and G6add9 in??

i need to know because im gonna create a solo over those chords...+ if any one knows the key of those chords and they got a good solo help me out.....thanks!!

It is C major.

How do u figure that out

??

you should know how the chords are made

first you have c major chords (1-3-5) of the c major scale , that's C-E-G then you have Em7 (1-b3-b7) that's g-b-d-e then you have sixth , added ninth ( 1-3-5-6-9) that's c -e -g -a-d so you have c -d -e-g-a -b and all these notes are notes from the c major scale

hope you understand a bit , it just comes down about knowing which notes are in the chords and in the scales