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amernassar
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smandalika
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heres another way to do it

from 1 and 2
(x + y) ^2 = x^2 + y^2 + 2*x*y = 13 + 2(6) = 25

or |x+ y| = 5

similarly

(x - y) ^2 = x^2 + y^2 - 2*x*y = 13 - 2(6) = 1

or |x- y| = 1

hence ans 6
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C, need both to determine that they are both + or -, and they are 2 and 3.
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ian7777
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smandalika
heres another way to do it

from 1 and 2
(x + y) ^2 = x^2 + y^2 + 2*x*y = 13 + 2(6) = 25

or |x+ y| = 5

similarly

(x - y) ^2 = x^2 + y^2 - 2*x*y = 13 - 2(6) = 1

or |x- y| = 1

hence ans 6


This is great. Love this method.
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Dan
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yes, a good question and an insightful answer! Saves time and energy.



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