Is |x| = |y|? (1) x = -y (2) x^2 = y^2

Question

Is |x| = |y|?

(1) x = -y
(2) x^2 = y^2

I found this question in GMAT Prep and selected ST2 as the answer but that's wrong.

Normally, x^2 would equal to lxl since it will contain both signs "positive as well as negative". How come st 1 is true?

Does it assume that since +x = -y, it must be true that -x is also equal to -y or?

What am I missing? :(

Thanks for your hep!

Siva2021 · Accepted Answer

You are asked whether |x|=|y| or in other words, is the distance of x from 0 = distance of y from 0 ? You would get a yes if x= y or x=-y. Lets evaluate the choices.

Per statement 1:x=−yx=−y . Clearly this is one of the conditions we are looking for. Assume 2-3 different values. x=2, y = -2 --> 2 and -2 are both 2 units from 0 . Similar for 3/-3 or 10/-10 etc. Thus this statement is sufficient.

Per statement 2: x2=y2x2=y2 ---> x=±yx=±y. Again both the cases, x=y and x=-y give you a "yes" for the question asked as is hence sufficient.

Both statements are sufficient ---> D is the correct answer.
Please give me kudos. I need them to unlock gmatclub tests.

AkshdeepS · Answer

Question:

Is |x| = |y|?

This can be represented in few ways as follow:

1. x = y

2. x = -y

3. -x = y

4. -x = -y

5. x^2 = y^2

If we can have any of these conditions, answer will be YES.

St 1: x = -y (Second condition) Sufficient

St 2: x^2 = y^2 (Fifth condition) Sufficient

(D)

ENGRTOMBA2018 · Answer

You are asked whether |x|=|y| or in other words, is the distance of x from 0 = distance of y from 0 ? You would get a yes if x= y or x=-y. Lets evaluate the choices.

Per statement 1: x=-y  . Clearly this is one of the conditions we are looking for. Assume 2-3 different values. x=2, y = -2 --> 2 and -2 are both 2 units from 0 . Similar for 3/-3 or 10/-10 etc. Thus this statement is sufficient.

Per statement 2:  x^2=y^2  --->  x= \pm y . Again both the cases, x=y and x=-y give you a "yes" for the question asked as is hence sufficient.

Both statements are sufficient ---> D is the correct answer.

sumit411 · Answer

The answer is D 1535218472739.jpg Sent from my ONEPLUS A3003 using GMAT Club Forum mobile app

AnkurGMAT20 · Answer

Bunuel , GMAT Prep question. Could you please tag it?

Bunuel · Answer

_______________
Done. Thank you!

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Is |x| = |y|? (1) x = -y (2) x^2 = y^2

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