Question

Помогите пожалуйста.

Answer 1

$\displaystyle \bigg( \sqrt{7-4 \sqrt{3} } -2\bigg)^2=\bigg(\sqrt{(2-\sqrt{3})^2}-2\bigg)^2=\big(|2-\sqrt{3}|-2\big)^2=\\ \\ \\ =\big(2-\sqrt{3}-2\big)^2=\big(-\sqrt{3}\big)^2=3$