Final answer:
The relation r on the set Z, the set of integers, is defined as xry if and only if x = y². The elements of r are determined by checking if the given pairs satisfy this condition. Only (5, 25) satisfies the condition.
Step-by-step explanation:
The relation r on the set Z, the set of integers, is defined as xry if and only if x = y². To determine which elements are in r, we need to check if the given pairs satisfy the condition. Let's go through each option:
- A. (64, 8): 8 is not equal to 64², so (64, 8) is not an element of r.
- B. (4,3): 3 is not equal to 4², so (4, 3) is not an element of r.
- C. (25,-5): -5 is not equal to 25², so (25, -5) is not an element of r.
- D. (5, 25): 25 is equal to 5², so (5, 25) is an element of r.
Therefore, the pairs that are elements of r are (5, 25).