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TAGS: GRE Prep Club Legend  Joined: 07 Jun 2014
Posts: 4857
GRE 1: Q167 V156 WE: Business Development (Energy and Utilities)
Followers: 105

Kudos [?]: 1783  , given: 397

If x – y = and x2 – y2 = 3, what is the value of x + y? [#permalink]
1
KUDOS
Expert's post 00:00

Question Stats: 100% (00:22) correct 0% (00:00) wrong based on 13 sessions
If $$x - y = \frac{1}{2}$$ and $$x^2 - y^2 = 3$$, what is the value of $$x + y$$?

[Reveal] Spoiler: OA
6

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Sandy
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Intern Joined: 05 Jan 2018
Posts: 32
Followers: 0

Kudos [?]: 16 , given: 8

Re: If x – y = and x2 – y2 = 3, what is the value of x + y? [#permalink]
Ans. 6
GRE Prep Club Legend  Joined: 07 Jun 2014
Posts: 4857
GRE 1: Q167 V156 WE: Business Development (Energy and Utilities)
Followers: 105

Kudos [?]: 1783 , given: 397

Re: If x – y = and x2 – y2 = 3, what is the value of x + y? [#permalink]
Expert's post
Explanation

The Difference of Squares (one of the “special products” you need to memorize for the exam) is $$x^2 - y^2 = (x + y)(x - y)$$.

Write this pattern on your paper and plug in the given values, solving for x + y:

$$x^2 - y^2 = (x + y)(x - y)$$
$$3 = (x + y)(\frac{1}{2})$$
$$6 = x + y$$
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Sandy
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Try our free Online GRE Test Re: If x – y = and x2 – y2 = 3, what is the value of x + y?   [#permalink] 28 Jul 2018, 16:09
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# If x – y = and x2 – y2 = 3, what is the value of x + y?  Question banks Downloads My Bookmarks Reviews Important topics Powered by phpBB © phpBB Group Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.