Evaluate the exponential function for the given value of \( x \). \( y=8^{x} \) for \( x=-2 / 3 \) The answer is \( \square \). (Type an integer or a simplified fraction.)

To evaluate the exponential function \( y = 8^{x} \) for \( x = -\frac{2}{3} \), we can start by rewriting 8 in terms of base 2. We know that \( 8 = 2^3 \), so: \[ y = (2^3)^{-2/3} \] When raising a power to another power, we multiply the exponents: \[ y = 2^{3 \cdot (-2/3)} = 2^{-2} \] Now, \( 2^{-2} \) can be simplified as: \[ y = \frac{1}{2^{2}} = \frac{1}{4} \] Thus, the answer is \( \frac{1}{4} \).