1. Identify the associative property:
a \cdot (b \cdot c) = (a \cdot b) \cdot c
2. Apply the property to the initial expression
-x \cdot (6 \cdot 25)
3. Rewrite the expression:
(-x \cdot 6) \cdot 25
Thus, the equivalent expression is (-x \cdot 6) \cdot 25.