`11+4sqrt6=8+2.2sqrt2.sqrt3+3=(2sqrt2+sqrt3)^2`
`11-4sqrt6=8-2.2sqrt2.sqrt3+3=(2sqrt2-sqrt3)^2`
`13+4sqrt10=8+2.2sqrt2.sqrt5+5=(2sqrt2+sqrt5)^2`
`13-4sqrt10=8-2.2sqrt2.sqrt5+5=(2sqrt2-sqrt5)^2`
\(11+4\sqrt{6}=\left(\sqrt{8}+\sqrt{3}\right)^2\\ 11-4\sqrt{6}=\left(\sqrt{8}-\sqrt{3}\right)^2\\ 13+4\sqrt{10}=\left(\sqrt{8}+\sqrt{5}\right)^2\\ 13-4\sqrt{10}=\left(\sqrt{8}-\sqrt{5}\right)^2\)