Question

(√8+2√7-√8-2√7) в квадрате​

Answer 1

$(\sqrt8+2\sqrt7-\sqrt8-2\sqrt7)^2=0^2=0\\\\\\\\\Big(\sqrt{8+2\sqrt7}-\sqrt{8-2\sqrt7}\ \Big)^2=\Big(\ \sqrt{(\sqrt7+1)^2}-\sqrt{\sqrt7-1)&^2}\ \Big)^2=\\\\\\=\Big(|\sqrt7+1|-|\sqrt7-1|\Big)^2=\Big((\sqrt7+1)-(\sqrt7-1)\Big)^2=2^2=4$