Answer: The simplified expression for y ^-3 is 1/y^3.
Step-by-step explanation: To understand this solution, it is important to understand the concept of negative exponents. When a number or variable is raised to a negative exponent, it means that the reciprocal of that number or variable is taken to the positive exponent.
In this case, y ^-3 can be rewritten as 1/y^3. This is because y^-3 is the same as 1/y^3. Therefore, the answer to this question is option (2) 1/y^3.