# Back to square one

Algebra Level 4

$\large \left( x+ \sqrt{x^2+\sqrt{2015}}\right)\left( y+ \sqrt{y^2+\sqrt{2015}}\right) = \sqrt{2015}$

If $$x$$ and $$y$$ are real numbers that satisfy the equation above, find the value of $$S$$ such that $$S = x+y$$.

Hint: Multiply both sides by with $$\left( \sqrt{x^2+\sqrt{2015}} - x\right)$$ and $$\left( \sqrt{y^2+\sqrt{2015}} - y\right)$$.

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