I don't know how to solve the next problem:
If we have two systems of parameters, $\{x_1,\ldots,x_n\}$ and $\{y_1,\ldots,y_n\}$ for a finitely generated $K$-algebra $A$ which is also an integral domain, and know that $A$ is free $K[x_1,\ldots,x_n]$-module how we prove that $A$ is free $K[y_1,\ldots,y_n]$-module?
System of parameters for $K$-algebra $A$ is an algebraically independent finite subset $\{x_1,\ldots,x_n\}$ of finite generated integral domain $A$ such that ring $A$ is integral over the polynomial subring $K[x_1,\ldots,x_n]$.
One should probably use Noether's normalization theorem.
Thank you very much for your help.