Write two integers with opposite signs, say 2 and -10. When we add them, we obtain -8. To have a sum of -20, the third integer must be -12 so the three possible integers are:

2,-10,-12

Write two integers with opposite signs, say 7 and -5. When we add them, we obtain 2. To have a sum of 10, the third integer must be 8 so the three possible integers are: 7,-5,8

2,-10,-12

Write two integers with opposite signs, say 7 and -5. When we add them, we obtain 2. To have a sum of 10, the third integer must be 8 so the three possible integers are: 7,-5,8