Answer:
The required cards can be -6 and -6.
Explanation:
Consider the provided integer -12.
We need to find the two cards whose sum is -12.
There are lots of choices for the two cards whose sum is -12.
Few choices are:
If we first card is -6 and the second card is also -6 then the sum will be -12:

If we first card is -4 and the second card is -8 then the sum will be -12:

If we first card is -10 and the second card is -2 then the sum will be -12:

Thus, the required cards can be -6 and -6.