You did right by subtracting 12 on both sides but after you subtracted you should have got -192 then you would divide 9 on both sides and once you have found what x equals to substitute what you have for x in your original equation
An interval may be described as horizontal, linear, or melodic in the music world, if that's what you were referring to.
Umm for me it’s comforting lol and it can be sometimes sad
1. Staff
3. Ledger line
5. flat
8. grand staff
11. goes up
sorry this was all I could remember for piano lessons
