Answer: x < 9
Step-by-step explanation: Actually, this is a LOT simpler than it seems.
So, looking at the problem, you know that the opposite value of x (opposite value is the number of spaces of a number away from 0), is less than 19 when you add it to 10. That said, |x| could be any rational number- whether positive or negative, as long as long as it equals less than 19 when added to 10. X could be -3, for example, because -3+10=7, which is <19. If, hypothetically, x were -3, then |x| would be 3, because -3 is 3 spaces from 0 (I just thought I'd explain it a little, because absolute value itself was confusing for me when I learned it at first).
Anyway, x could not be any number greater than 9 because than it would equal more than 19, and it can't be 9 because that wouldn't be less than 19. Does that make sense?