What is the equation of the plane that contains the triangle shown in the diagram?
2x + 3y + z = 6
2x + 3y + 6z = 12
3x + 2y + 6z = 0
6x + 2y + 3z = 18
2x + 3y + z = 6
2x + 3y + 6z = 12
3x + 2y + 6z = 0
6x + 2y + 3z = 18