first we solve the multiplication
[tex]\begin{gathered} \frac{6x^2y}{z}+\frac{(3\times2)x(y^2\times y^2)}{(z\times z)x}^{} \\ \frac{6x^2y}{z}+\frac{6xy^4}{z^2x} \\ \frac{6x^2y}{z}+\frac{6y^4}{z^2} \end{gathered}[/tex]now do the sum
[tex]\begin{gathered} \frac{(6x^2y\times z^2)+(6xy^4\times z)}{(z\times z^2)} \\ \\ \frac{6x^2z^2y+6y^4z^{}}{z^3} \\ \\ \frac{6x^2y}{z}+\frac{6y^4}{z^2} \end{gathered}[/tex]