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If x - y = sqrt(3) and x + y = 2, then xy = ?

 May 15, 2020
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x - y  = sqrt (3)

x + y =  2

 

Square both sides  of these

 

x^2  - 2xy  + y^2   =   3

x^2  +2xy   + y^2  =   4           subtract the first equation from the second and we have that

 

4xy  =  1            divide both sides by  4

 

xy  = 1/4

 

 

cool cool cool

 May 15, 2020
edited by CPhill  May 15, 2020

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