Question

\(\left(\sqrt{28}-2\sqrt{3}+\sqrt{7}\right)\sqrt{7}+\sqrt{84}\)

Answer 1

\(\left(\sqrt{28}-2\sqrt{3}+\sqrt{7}\right)\sqrt{7}+\sqrt{84}\)

\(=\sqrt{196}-\sqrt{84}+7+\sqrt{84}\)

\(=14+7=21\)

Answer 2

mk không chép đề

(2\(\sqrt{7}\)-2\(\sqrt{3}\)+\(\sqrt{7}\))\(\sqrt{7}\) +2\(\sqrt{21}\)

=14 -2\(\sqrt{21}\)+7 +2\(\sqrt{21}\)

=21