16 tháng 6 2021 lúc 9:15
\(a,\sqrt{22-8\sqrt{6}}\)
\(\sqrt{4^2-8\sqrt{6}+\sqrt{6}^2}\)
\(\sqrt{\left(4-\sqrt{6}\right)^2}=\left|4-\sqrt{6}\right|\)
\(4>\sqrt{6}< =>\left|4-\sqrt{6}\right|=4-\sqrt{6}\)
\(b,\sqrt{16-6\sqrt{7}}\)
\(\sqrt{3^2-6\sqrt{7}+\sqrt{7}^2}\)
\(\sqrt{\left(3-\sqrt{7}\right)^2}\)
\(\left|3-\sqrt{7}\right|\)
\(=3-\sqrt{7}\)
\(c,\sqrt{9-4\sqrt{2}}\)
\(\sqrt{9-2.2\sqrt{2}}\)
\(\sqrt{\left(2\sqrt{2}\right)^2-2.2\sqrt{2}+1}\)
\(\sqrt{\left(2\sqrt{2}-1\right)^2}\)
\(2\sqrt{2}>1\)
\(\left|2\sqrt{2}-1\right|=2\sqrt{2}-1\)
