Solve the Double Absolute Value Equation: -|-y²|

To solve this problem, let's break it down into the following steps:

• Step 1: Recognize that inside the absolute value, we have $-y^2$. Since $y^2$ is non-negative, $-y^2$ is less than or equal to zero.
• Step 2: Apply the absolute value: Since $-y^2 \leq 0$, we use the property $|-a| = -(-a)$, resulting in $\left|-y^2\right| = y^2$.
• Step 3: Apply the outer negative sign, $-\left|-y^2\right|$, which simplifies to $-y^2$.

Therefore, the solution to the problem is correctly identified as $-y^2$.