An expression is shown below (x^4/3)(x^2/3)

(x^4/3)(x^2/3) =

When you multiply powers with the same base, write the ame base and add the exponents.
Here the common base is x. The exponents are 4/3 and 2/3. The exponents are added.

= x^(4/3 + 2/3)

= x^(6/3)

= x^2