Answer
No solution as $x \ne 4$
Work Step by Step
We have $\dfrac{3x}{x-4}=\dfrac{2(x-4)}{x-4}+\dfrac{12}{x-4}$
Re-write as: $3x=2(x-4)+12$
or, $3x=2x-8+12$
or, $x =4$
and $x -4 \ne 0 \implies x \ne 4$
No solution since there is the domain restriction $x \ne 4$
