how do i solve 3 (2y-4)=8y+9-9y

3(2y - 4) = 8y + 9 - 9y

Distribute 3:
6y - 12 = 8y + 9 - 9y

Combine like terms:
6y - 12 = -y + 9

Add y to both sides:
7y - 12 = 9 

Add 12 to both sides:
7y = 21

Divide both sides by 3:
y = 3