If $$x+2 = y$$ and $$y+4x = 12$$, then $$x=$$． 
Overseas Competition->Knowledge Point->Calculation Modules->Basic Concepts of Equation->Linear Equations with Multiple Variables
If $$x+2=y$$, then $$x=y-2$$.  We can get $$y+4(y-2)=12$$ implying that $$y=4$$ and hence $$x=y-2=2$$. 