[อัจฉริยะข้ามภพ]

$$ ( 11-2\sqrt{30} )^{\frac{x}{2}} = \sqrt{6} + \sqrt{5} $$
$$((\sqrt{6} -\sqrt{5} )^2)^\frac{x}{2} =\sqrt{6} + \sqrt{5} * \frac{\sqrt{6} - \sqrt{5}}{\sqrt{6} - \sqrt{5}} $$
$$(\sqrt{6} -\sqrt{5} )^x=(\sqrt{6} - \sqrt{5})^{-1}$$