In the initial statement:
Is |a| + |b| > |a + b| ?
If a > 0 and b > 0, then
|a| = a
|b| = b
|a + b| = a + b
So |a| + |b| = |a + b|
If a < 0 and b < 0, then
|a| = -a
|b| = -b
|a + b| = -a - b
So |a| + |b| = |a + b|
Only if one is positive and one is negative will |a| + |b| > |a + b|, because when one is positive and one is negative |a + b| will be closer to 0 than the individual |a| + |b|.
So a translation of this question is:
Do a and b have different signs (in which case the inequality is true), or the same sign (in which case they are equal and it is false)?
With this in mind, the statements tell us that b < 0 but nothing about the sign of a.
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