For this case, we have that by definition, in mathematics, an ordered pair is given by a pair of mathematical objects, in which one element and another is distinguished. 
They are usually denoted by: 

In this case we want to construct ordered pairs with 
 .
. 
Then, "y" can take any value of the real numbers to form ordered pairs with

Examples: 
(2, -1); (2.5); (2.80) ... 
Answer: 
"y" can take any value