xy >= 0
------------
V(xy) = 6 => xy = 36
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x^2 + y^2 + 2xy - 2xy = 97
(x+y)^2 - 2xy = 97
(x+y)^2 - 2*36 = 97
(x+y)^2 = 169
x+y = 13
y = 13-x
-------------
x*(13-x) = 36
x^2 - 13x + 36 = 0
x1 = 4
x2 = 9
y1 = 9
y2 = 4