GMAT Data Sufficiency (DS) | Re: If ab > 0, what is the value of (a + b)2 (1) a2 = 4 (2) b2 = 1

If ab>0, it means both a and b have same sign.
Either both a and b are positive or both a and b are negative

We want the value of (a+b)^2

Obviously, none of the statements individually take us to the answer, because 1st statement tells us only about 'a'; while second statement tells us only about 'b'.

Lets combine the two statements.
a^2 = 4, so a can be 2 or -2
b^2 = 1, so b can be 1 or -1

But we know that both a and b have same signs, Either a=2, b=1 OR a=-2, b=-1
So Either a+b = 3
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