dmmk wrote:
prasannar wrote:
Is x^2 equal to xy?
(1) x2 – y2 = (x + 5)(y - 5)
(2) x = y
ritula wrote:
(1)x^2-y^2=(x+y)(x-y)=(x + 5)(y - 5)
so y=5 but no information abt x so insufficient
(2) x=y
multiplying both sides by x
x^2=xy sufficient
So answer should be B
FN wrote:
this should be B..
x^2-y^2=(x-y)(x+y)..
we have (x+5)(y-5)... (y-5) is not equal to (x-y)
here x is negative...so insuff
Can someone please explain this DS problem in more detail? Bunuel ??... Please can you help! TY
Is x^2 equal to xy?Question: is \(x^2=xy\)? --> \(x(x-y)=0\) --> Equation holds true if \(x=0\)
or/and \(x=y\).
So, basically question asks: Is \(x=0\)
or/and \(x=y\) true?
Obviously statement (2) is sufficient, as it gives directly that \(x=y\).
(1) x^2 – y^2 = (x + 5)(y - 5) --> \((x+y)(x-y)=(x + 5)(y-5)\)
If \(y=5\) --> \((x+5)(x-5)=(x+5)(5-5)\) --> \((x+5)(x-5)=0\) --> Either \(x=5=y\) and in this case answer to the question is YES
OR \(x=-5\), hence \(x\) is not equal to \(y\) (nor to zero) and in this case answer to the question is NO. So two different answers.
Not sufficient.
Answer: B.
OPEN DISCUSSION OF THIS QUESTION IS HERE: is-x-2-equal-to-xy-88034.html _________________