Is xy x^2 ? (1) y x (2) y 0

Question

Is xy > x^2 ?

(1) y > x

(2) y > 0

m1033512 · Answer

IMO E

statement 1.

take x = -3 and y = -2 and 2 
for y = -2 ,it is true 
for y = +2 , it is false

insufficinet

statement 2

for y >0 , but x can be negative also, so insufficient

Even if we combine together, we still can not decide the sign of x which ia essential to make LHS positive

award kudos if helpful

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rishabhshreyas14 · Answer

xy > x^2

Can't we rewrite this statement as xy>xx -->>>> (dividing by x both sides) y>x ?

LeoN88 · Answer

Stem: xy > x^2

Statement 1. y>x 
y x
3 2 True
2 -3 False

Statement 2. y>0
y x
3 2 True
2 -3 False

1+2
y x
3 2 True
2 -3 False

E, Insufficient.

LeoN88 · Answer

rishabhshreyas14 
We can't; check the video

https://www.youtube.com/watch?v=S_fjYmCtvy0

CC  GMATPrepNow

BrentGMATPrepNow · Answer

rishabhshreyas14 , I believe the video below is the one  LeoN88  meant to reference: 
The part about dividing by variables starts around 2:30

https://www.youtube.com/watch?v=Od98BOicIq4

Businessconquerer · Answer

I HAVE A POSSIBLY SIMPLER APPROACH IF IT STRIKES YOU

WE CAN REWRITE THE TERMS I SUPPOSE LIKE THIS
x(y-x)>0

what does this mean?
neg x neg
or
pos x pos

if x = -ve
y= smaller negative: then yes

if x= +ve
y= bigger positive: for inequality to be true

looking at the statements, y>x : we can get both no/yes
y>0 again two cases

combining: we still cannot say about x.
E

Shrey9 · Answer

Can anyone tell me if I am doing the right way ?

given
xy > x^2
xy-x^2>0
x(y-x) >0
there exist two cases now for the question now
either  x > 0 
or y-x >0  or y>x

Now lets look at the statements

1) says  y>x  but doesn't tell us anything about x>0 or x <0 
therefore not sufficient

2) says y>0 but we don't know if x > 0 or not..
therefore, not sufficient

Combining 1 and 2
 y>x  from 1
and y> 0 from 2
but what about x > 0 ?

therefore, not sufficient 
hence E

chetan2u · Answer

Do we know whether x is positive or negative? …..No So, bring it to one side xy-x^2>0……….x(y-x)>0 two cases If x>0, then y>x. => y>x>0 If x<0, then y yx Nothing about x. (2) y>0 Nothing about x Combined Nothing about x. We still do not know whether x is positive or negative. E

Is xy > x^2 ? (1) y > x (2) y > 0

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