This is Functions and Statistics Class:

[tex] \sqrt[6]{x} . \sqrt[4]{ {y}^{3} } \\ = {x}^{ \frac{1}{6} } . {y}^{ \frac{3}{4} } \\ = {x}^{ - 6} . {y}^{ \frac{3}{4} } [/tex]
Hope you could get an idea from here.
Doubt clarification - use comment section.