Let $f(x) = \frac{3\sin\!\left(x\right)}{6\sin\!\left(x\right)+2\cos\!\left(x\right)}$.

Then $f'(x) =$ .

Write the equation of the tangent line to the graph of $y=f(x)$ at $x = 0$ written in the form $y=mx+b$:
$y =$