If $\displaystyle x= \frac{e^{3z}}{y^4}$ then $z(x,y)$? If $\displaystyle x= \frac{e^{3z}}{y^4}$ then $z(x,y)$ ?
I know that we subtract powers in fractions but how do we solve it when there is a variable $3z$? And what is what is $z(x,y)$?
This question is supposed to be easy and it irritate me that I can't solve it. Can anyone please help?

Here is how you advance

$$  e^{3z}= xy^4  \implies z=\frac{1}{3} \ln(x y^4). $$

