I think the second statement is a-b>0
If ax + b = 0, is x > 0?
a. a + b > 0
b. a �" b > 0
Anyways, here is how I would solve it
ax+b=0
x=-b/a
a. a+b>0
Either a or b could be 0. Each one gives different answers. So, insufficient.
b. a-b>0
That means a>b. But b could be 0 or any other number. Say a=10 b=5 or a=8 b=0.
So, insufficient.
Combining, we still don't know either a or b is negative. All we know is
a and b both can be positive - which will make x negative.
or
a is positive and b is negative - which will make x positive.
So answer should be E.
GMAT Prep DS question.
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mridula wrote:If ax + b = 0, is x > 0?
a. a + b > 0
b. a -- b > 0
Please provide explanation. OA to follow.
ax+b=0
x= (-b/a)
Is -b/a > 0 ??
1) a > - b ...Insuff doesnt say much.. try with numbers
2) a > b...Insuff doesnt say much
Together,
a + b > 0
a - b > 0
ADD
2a > 0
Therefore a > 0
No clue about b ...
Therfore E
