1. The domain set of C = {(2,5),(2,6),(2,7)} is the set of all first elements of the ordered pairs.
Therefore, domain set of C = {2}
2. The range set of E ={(3, 3),(4, 4),(5, 5),(6, 6)} is the set of all second elements of the ordered pairs.
Therefore, range set of E = {3,4,5,6}
3. We need to find the range and domain of F = {(x, y) | x + y = 10}.
Clearly, the domain is the set of all real numbers.
Also, if x is a real number, then 10 - x is also a real number.
We have, x + y = 10
y = 10 - x
So, y is also a real number.
Therefore, range and domain of F = {all real numbers}
4. We need to find the range and domain of P = {(x, y) | y = 3}.
Clearly, the domain is the set of all real numbers.
Since, the y = 3 (the second element of the ordered pair), the range is the singleton set {2}.
Hence, domain = {all real numbers} and range = {y : y = 3}