Question 1186558
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There are many possible sets, containing the number -15 as an element.


Some of them are


    -  the set of all real numbers R;


    - the set of all integer numbers Z;


    - the set of all real negative numbers;


    - the set of all integer negative numbers;


    - the set of all integer odd numbers;


    - the set of all rational numbers;


and many other sets.



On your choice . . .