Final answer:
The completely simplified expression is 25c^8d^
Step-by-step explanation:
In the expression ((5c)^3 x c x d^6 / (5d)^2) ^2, we can start by simplifying the exponents:
((5c)^3 x c^1 x d^6 / (5d)^2) ^2
(125c^3 x c x d^6 / 25d^2) ^2
Next, we can simplify the numerators and denominators:
(125c^4d^6 / 25d^2) ^2
Finally, we can simplify the expression within the parentheses:
(5c^4d^4) ^2 = 25c^8d^8
So, the completely simplified expression is 25c^8d^8.