Question

СПРОСТІТЬ ВИРАЗ: √8-2√7

Answer 1

$\displaystyle\bf\\\sqrt{8-2\sqrt{7} }=\sqrt{7-2\sqrt{7} +1} =\sqrt{(\sqrt{7})^{2}-2\sqrt{7} +1^{2} } =\\\\\\=\sqrt{(\sqrt{7}-1)^{2} }=|\sqrt{7} -1|=\sqrt{7} -1$