Combine similar terms and apply the operation. Do NOT evaluate or simplify.
1) 2x + 4 + 3x
2) 12 + 5x -8
3) 2x^2 + 3x^2 + 4x
4) 5ax - 12 - ax
5) 4xy + 2x + 3xy + x
1) 2x + 4 + 3x
2) 12 + 5x -8
3) 2x^2 + 3x^2 + 4x
4) 5ax - 12 - ax
5) 4xy + 2x + 3xy + x