gmat prep variables

bumpy bump

This is little tricky...
might confuse in eaxm condition.at leat i would have confused..

however..

From the question itself : ax+b=0 (given)
so x=-(b/a)

From 1 : a+b>0 here either both at the same time can be positive; any one of them can be negative at a time.
If both are positive simoulteneously then x could be negative ; if one of them is negative x would be positive ! hence not determinable.In sufficient.

From 2 : a>b ; if both are positive then x could be negative (from question we can compare); if both are negative then x would be positive; There can be other combinations also.in any case whether x is positive or negative can't be determined.In sufficient.

When we combine them we can't even determine whether x coule be <o> 0.So insufficient.