The answer is incorrect because 12 should be negative not positive.
Step-by-step explanation:
1. 19 + -31 = - 12
2. Twelve is negative because if you were to start off at -31 and add 19 the answer would remain negative since -31 in a sense is "bigger" than 19. You would need more of a positive number to make -31 positive such as 40.
