Is it C?yvonne12 wrote:is xy>0
1. x-y>-2
2. x-2y<-6
please explain
1 - insufficient. Take x = 5, y= 3 and x = 5, y = -3. xy can be positive
or negative.
2 - insufficient. Take x = 5, y = 6 and x = -5, y = 6. xy can be positive
or negative.
Together,
x > y-2 & x < 2y-6
y-2 < x < 2y-6
We can see that the above falls apart for all values y < 4 and x < 2.
So, x and y have to be positive and hence C.
Alternatively, I think we can do the following
x-y > -2
2y-x > 6
Adding, we get y > 4. And so x > 2. Hence sufficient and so C.
OA please.
