Answer
$\{ 4 \}$
Work Step by Step
Step 1. Graph $y=4x-3(4-2x)$ as shown in the figure (red).
Step 2. Graph $y=2(x-3)+6x+2$ as shown in the figure (blue).
Step 3. Find the intersect at point $(4,28)$, thus $x=4$.
Step 4. The solution is $\{ 4 \}$