# How do I find the derivative of y=(ln(3x))/(3x?

Given: $y = f \frac{x}{g} \left(x\right)$
Then: $y ' = \frac{f ' \left(x\right) g \left(x\right) - f \left(x\right) g ' \left(x\right)}{g \left(x\right)} ^ 2$
$y ' = \frac{\frac{3}{3 x} \cdot 3 x - \ln \left(3 x\right) \cdot 3}{3 x} ^ 2 =$
$= \frac{3 - 3 \ln \left(3 x\right)}{9 {x}^{2}} = \frac{1 - \ln \left(3 x\right)}{3 {x}^{2}}$