Answer:
Answer is - 9 + 12 because they have different signs in front of each integer. (if that is what the question means)
Step-by-step explanation:
Negative sign x negative sign = positive sign
-9 - (-12) = -9 + 12
-9 - 12
-12 - 9 = -9 - 12
12 - (-9) = 12 + 9 = 9 + 12
