Can you help Combine like terms

12 g + 7g

Combine like terms
6x + 3y + 5x

simplify
4(x+3) -5

Can you help solve
6y + 2y = 16

are these all different problems?

1. 12g+7g=21g

2.6x+3y+5x=11x+3y

3.4(x+3)-5
=4x+12-5
=4x+7

4. 6y+2y=16
8y=16
y=16/8
y=2