First, identify the associative property of multiplication, which states that for any numbers \(a\), \(b\), and \(c\), it holds that \((a \cdot b) \cdot c = a \cdot (b \cdot c)\). Applying the associative property, we have:
1. Original expression:   -x \cdot (6 \cdot 25)  
2. Apply the associative property:   (-x \cdot 6) \cdot 25  
The equivalent expression is  (-x \cdot 6) \cdot 25  .