\[y^{2} = (\sqrt{11} + \sqrt{2})(\sqrt{11} - \sqrt{2})\]
\[y^{2} = \left( \sqrt{11} \right)^{2} - \left( \sqrt{2} \right)^{2}\]
\[y^{2} = 11 - 2\]
\[y^{2} = 9\]
\[y = \pm 3.\]