Question

решите
$2 \times \sqrt{4 + \sqrt{7} }$

Answer 1

$2 \times \sqrt{4 + \sqrt{7} } =\sqrt{4(4 + \sqrt{7} )} = \sqrt{16 +4\sqrt{7} } = \sqrt{14+4\sqrt{7} +2} =\\\sqrt{(\sqrt{14})^2+2 \sqrt{28} +(\sqrt2)^2} =\sqrt{(\sqrt{14}+\sqrt2)^2}=\sqrt{14}+\sqrt2$