To evaluate the expression \( \sqrt{36} \times x^{5/3} \), we first simplify \( \sqrt{36} \), which is equal to \( 6 \). Since \( x^{5/3} \) can be rational or irrational depending on the value of \( x \), the product \( 6 \times x^{5/3} \) will be rational if \( x^{5/3} \) is rational, and irrational if \( x^{5/3} \) is irrational.
Expression:
\[ \sqrt{36} \cdot x^{5/3} = 6 \cdot x^{5/3} \]
Product:
\[ 6x^{5/3} \]
Thus, the rationality of the product depends on \( x \). For example, if \( x = 1 \) (rational), then the product is \( 6 \); if \( x = 2 \) (rational), then the product is \( 6 \cdot 2^{5/3} \) (which can be expressed as irrational). Therefore, the product can be either rational or irrational depending on the value of \( x \).