If \(a\) is non-negative, is \(x^2 + y^2 > 4a ?\)

[Gmat_mission]

If \(a\) is non-negative, is \(x^2 + y^2 > 4a ?\)

(1) \((x + y)^2 = 9a\)
(2) \((x - y)^2 = a\)

Answer: E

Source: Manhattan GMAT