This is a linear equation. The farthest you can get is to:
1) Divide both sides of the equation by 2, getting x + 3y = 16.
2) Subtract the y part, giving you x = 16 - 3y.
"Addition method" and "substitution method" are typical terms describing methods of solving sets of equations. There is only one equation, and it cannot be "solved" by addition or substitution methods.